Use Of Antibiotics In Food Animals Research Articles

The effect of information provision on consumers’ risk perceptions of, support for a ban, and behavioral intention towards the preventive use of antibiotics in food animals

BackgroundAntibiotics have been widely used in feed and drinking water for food animals to prevent them from getting sick. Such preventive use of antibiotics has become a contributor to increasing antibiotic resistance and thus poses threats to human health. However, consumers have little knowledge about this practice and the associated health risks of increasing transmission of antibiotic residues and antibiotic resistant bacteria. This study aimed to examine the effect of information provision on consumers’ risk perceptions, support for a ban, and behavioral intention regarding the preventive use of antibiotics in food animals. Especially, the study sought to test two competing hypotheses which were informed by two theoretical perspectives of fear appeal theory — the linear model and the plateau effect model. The former suggested that providing information on the health risks of both antibiotic residues and antibiotic resistant bacteria would have a stronger effect compared to providing information on only one of them, while the latter posited that providing information on both risks might not have additional influence, as the effect of information on either risk could reach the plateau.MethodsAn experimental study with four conditions was conducted where participants read different information on the health risks associated with the preventive use first and then answered questions regarding consumers’ risk perceptions, support for a ban, and behavioral intention regarding the preventive use. Condition 1 was the control condition, where basic information about antibiotics, antibiotic resistance, and the preventive use was provided. Condition 2 and Condition 3 further added information on the health risk of antibiotic residues (Condition 2) and antibiotic resistant bacteria (Condition 3) due to the preventive use, respectively. Condition 4 provided all information contained in the first three conditions.ResultsThe results showed that compared to participants in the control condition, participants in Conditions 2-4 reported higher risk perceptions, stronger support for a ban on the preventive use, and a higher intention to buy meat produced without the preventive use of antibiotics. However, there were no significant differences in these factors between Conditions 2-4, indicating that providing information on the health risk of either antibiotic residues, or antibiotic resistant bacteria, or both, has similar effect on these variables. That is, the hypothesis based on the plateau effect model was supported.ConclusionsThe findings suggested that informing the public with the health risk of either antibiotic residues or antibiotic resistant bacteria associated with the preventive use is effective enough to reach plateau effect in increasing risk perceptions, support for a ban, and behavioral intention, which has important implications for policymakers and livestock industries to develop effective communication strategies to promote responsible antibiotic use in food animals.

Consumer Preferences and Attitudes towards Antibiotic Use in Food Animals.

Antimicrobial resistance (AMR) is one of the major challenges faced by society, with the real threat of the failure of many medical procedures. Antibiotics are also used in livestock production and provide a potential pathway to increasing AMR. The central challenge involves ensuring animal health and welfare while securing the long-term effectiveness of antibiotics. This paper reports the results of a survey of 5693 respondents from the customer panels of four major UK supermarkets regarding preferences and attitudes towards antibiotic use in food animals, and their perspectives on how the balance between animal welfare and human benefit can be achieved. The results of these surveys are consistent with those from other countries that found that consumers generally have limited knowledge about antibiotic use in agriculture and AMR, with around 50% responding "don't know" to many questions. There was agreement about the benefits of antibiotics outweighing harm, with 40% agreeing that, overall, the use of antibiotics to treat disease in farm animals delivers more benefit than harm. However, 44% neither agreed nor disagreed, indicating a high level of uncertainty and a situation that is potentially unstable. The seriousness of the AMR challenge is such that continued action for the more discriminating use of antibiotics must continue.

In Vivo Efficacy of Echinops spinosus Decoction as a Therapeutic for Cows at Risk of Clinical Endometritis.

Clinical endometritis (CE) is a multifactorial disease of dairy animals. Retained fetal membranes (RFM) and metritis are the major risk factors of CE in dairy cows. Because uterine inflammation affects the profitability of the dairy industry, antibiotics and hormonal therapies are commonly used to mitigate against the disease. However, the One-Health concept aims to reduce antibiotic use in food animals to avoid the emergence of drug resistance or residues in milk or meat. Thus, phytotherapy may represent a good alternative to antibiotics in food animals. Echinops spinosus (E. spinosus) is a natural plant known to have therapeutic, anti-inflammatory, antimicrobial, and wound-healing properties in vitro. The aim of the present study was to investigate the efficacy of E. spinosus as a preventive strategy for CE in dairy cows with other postpartum complications. Holstein-Friesian cows (n = 36) diagnosed with RFM or metritis enrolled in the study were allocated into three groups. One group received antibiotic treatment. Another group received prostaglandin injection (PG). The experimental group received E. spinosus decoction orally. As a control group, eutocic cows (n = 36), without RFM and metritis were included in the study. The efficiency of the treatment was based on the occurrence of CE and improved reproductive outcomes. At 30 ± 2 DPP, CE was diagnosed in 25%, 58.34%, and 75% in antibiotic, PG, and E. spinosus groups, respectively (p < 0.05). There were no differences between the groups at 55 ± 5 DPP (16.67%, 33.44%, and 41.67% in antibiotic, PG and E. spinosus groups, respectively, p > 0.05). The E. spinosus group had the longest open days, lowest conception rate at 150 DPP, and highest number of services per conception. Oral E. spinosus extract is ineffective as a therapeutic for cows at risk of CE. These findings may pave the way for future innovative strategies employing E. spinosus to protect cattle against endometritis.

The Governance of UK Dairy Antibiotic Use: Industry-Led Policy in Action

This article analyses the progress made in the UK with regard to tackling antibiotic “misuse and overuse” in food-producing animals. Moving beyond statistical realities, the paper examines how the UK's industry-led policy approach is shaping practice. Using a multi-sited ethnography situated in Actor Network Theory and Callon's sociology of markets, the UK dairy supply chain policies and practices were studied. Findings reveal that dairy industry policies only partially address the complex network of people, animals, and the environment in which dairy antibiotics circulate. Antibiotic “misuse and overuse” in agriculture is far from a behavioural matter, with solely farmers and veterinarians to blame. Instead, antibiotic use in food animals is embedded in complex economic networks that constrain radical changes in dairy husbandry management and antibiotic use on farms. More attention toward the needs of the dairy supply chain actors and wider environmental considerations is essential to reduce the dairy sector's dependency on antibiotics and support transition toward responsible farming in the UK.

Antibiotic use in food animals worldwide, with a focus on Africa: Pluses and minuses.

Antibiotics are frequently used in food animal production in developing countries to promote the well-being and growth of animals. This practice provides some economic benefits to producers and consumers at large. Nevertheless, this practice is also associated with a number of concerns. A major concern has been that repeatedly exposing these animals to small doses of antibiotics contributes significantly to antimicrobial resistance, since a good fraction of the antibiotics used are the same or surrogates of antibiotics used in human therapeutic practices. Studies over decades have shown an explicit relationship between antimicrobial use and antimicrobial resistance in veterinary science. Many antibiotics can be purchased over the counter in African countries, and antibiotic resistance is an important issue to address in this region. This review examines some of the risks and benefits associated with antibiotic use in food animals. We conclude that the use of antibiotics in food animal production constitutes a major contributing factor to the current antimicrobial resistance crisis and that antibiotics should only be used for the treatment of sick animals based on prior diagnosis of disease.

Understanding policy dilemmas around antibiotic use in food animals & offering potential solutions.

The looming concern of antimicrobial resistance (AMR) has prompted the government of many countries of the world to act upon and come up with the guidelines, comprehensive recommendations and policies concerning prudent use of antibiotics and containment of AMR. However, such initiatives from countries with high incidence of antibiotic-resistant bacteria in food animals are still in infancy. This review highlights the existing global policies on antibiotics use in food animals along with details of the various Indian policies and guidelines. In India, in spite of availability of integrated policies for livestock, poultry and aquaculture sector, uniform regulations with coordinated initiative are needed to formulate strict policies regarding antimicrobial use both in humans and animals. In an attempt to create effective framework to tackle the AMR, the Indian Council of Medical Research initiated a series of dialogues with various stakeholders and suggested various action points for urgent implementation. This review summarizes the recommendations made during the various consultations. The overarching aim of this review is to clearly delineate the action points which need to be carried out urgently to regulate the antibiotic use in animals.

Antimicrobial Resistance is a Global Problem

Infectious agents resistance to antimicrobials remains a challenging open problem of health care around the world. As a result, treatment-induced infections pose a serious threat to public health in general. This problem has become so important that the overwhelming majority of countries consider it a threat to the national security. Resistance to antimicrobials threatens to offset the very fundamentals of modern medicine and the sustainability of the public health system effective global response to a permanent infectious diseases threat. Today, antimicrobial resistance issues can be tackled provided that one implements an effective One Health approach (the principle of human and animal health interrelation), assuming that there is a coordination between different sectors and subjects, including experts in medicine, veterinary medicine, agriculture, ecology, and well-informed consumers. To ensure effectiveness of treatment, action is urgently needed to counteract the further development and spread of antibiotic resistance, which is driven by antibiotic use in all sectors. Since this resistance has no ecological, sectoral or geographical borders, its appearance in one sector affects resistance in other sectors. National authorities, veterinarians, physicians, patients and farmers all have key roles in preserving the power of antibiotics. The prevention and containment of antibiotic resistance therefore requires addressing all risk factors for the development and spread of antibiotic resistance across the full spectrum of conditions, sectors, settings (from health care to use in food-animal production) and countries. This article explores the options for prevention and containment of antibiotic resistance in the food-chain through national coordination, including the regulation and reduction of antibiotic use in food animals, training and capacity building, surveillance of resistance trends and antibiotic usage, promotion of knowledge and research, and advocacy and communication to raise awareness of the issues. The article suggests possible ways for adopting a holistic, intersectoral, multifaceted approach to this growing problem.

Боротьба з резистентністю до антибіотиків на принципах концепції «Єдине здоров’я»

Частота інфекцій, спричинених антибіотикорезистентними бактеріями, збільшується серед населення і в медичних установах, тому ці інфекції є важливою медико-санітарною проблемою, яка кидає виклик системам охорони здоров’я в різних країнах. Унаслідок надмірного та неправильного застосування антибіотиків у бактерій, які містяться в організмі людей і тварин, може розвинутися стійкість до цих препаратів, тому інфекції, котрі раніше добре піддавалися лікуванню антибіотиками, стає важко, а іноді — неможливо вилікувати.
 Для забезпечення ефективності лікування необхідно терміново вжити заходів з протидії подальшому формуванню та поширенню стійкості до антибіотиків унаслідок їх застосування у багатьох галузях. Оскільки стійкість не має екологічних, галузевих або географічних кордонів, її поява в одній галузі призводить до формування резистентності в інших галузях. Національні керівні органи, ветеринарні працівники, фермери, лікарі та пацієнти відіграють ключову роль у збереженні активності антибіотиків.
 Висвітлено можливості для запобігання і стримування стійкості до антибіотиків на національному та міжнародному рівнях, зокрема регламентацію раціонального застосування антибіотиків у медицині, ветеринарії, сільському господарстві та виробництві харчових продуктів, підготовку фахівців, нагляд за тенденціями в резистентності та застосуванні антибіотиків, поширення інформації, проведення наукових досліджень, освітню та роз’яснювальну роботу для привернення уваги до проблеми. Запропоновано можливі шляхи для розробки цілісного міжвідомчого та мультидисциплінарного підходу на принципах концепції «Єдине здоров’я» для вирішення цієї важливої проблеми.

Selective Induced Altered Coccidians to Immunize and Prevent Enteritis.

Microbiomic flora in digestive tract is pivotal to the state of our health and disease. Antibiotics affect GI, control composition of microbiome, and shift equilibrium from health into disease status. Coccidiosis causes gastrointestinal inflammation. Antibiotic additives contaminate animal products and enter food chain, consumed by humans with possible allergic, antibiotic resistance and enigmatic side effects. Purposed study induced nonpathogenic, immunogenic organisms to protect against disease and abolish antibiotics' use in food animals and side effects in man. Diverse species of Coccidia were used as model. Immature organisms were treated with serial purification procedure prior to developmental stages to obtain altered strains. Chicks received oral gavage immunized with serial low doses of normal or altered organisms or sham treatment and were challenged with high infective normal organisms to compare pathogenicity and immunogenicity. Mature induced altered forms of E. tenella and E. necatrix lacked developmental stage of “sporocysts” and contained free sporozoites. In contrast, E. maxima progressed to normal forms or did not mature at all. Animals that received altered forms were considerably protected with higher weight gain and antibody titers against challenge infection compared to those that received normal organisms (p < 0.05). This is the first report to induce selected protective altered organisms for possible preventive measures to minimize antibiotic use in food animals.

Cambodia: the first national study of antibiotic prescribing and resistance using mixed methods approach

Antibiotic resistance is present globally. Contributing factors in Cambodia include self-medication by the community, uncontrolled sale of antibiotics and unregulated antibiotic use in food animals.

Food safety in an international perspective

Access to safe food is a basic individual right. Yet, as stated by Dr. Margaret Chan, Director-General of the World Health Organization (WHO), ‘‘food safety is a hidden, and often overlooked, problem’’ (Chan 2014). Indeed, foodborne disease represents a significant burden to public health throughout the world. Unsafe food can lead to a range of health problems, with new threats to food safety constantly emerging. Food that contains harmful bacteria, viruses, parasites or chemical substances is responsible for more than 200 diseases, both acute and chronic, ranging from diarrhoea to cancer. WHO estimates that the burden of foodborne disease is much higher than currently reported (WHO Regional Office for Europe 2015; WHO 2015a). The human food chain is longer and more complex than ever before, and demographic, cultural, economic and environmental developments—globalized trade, travel and migration, ageing populations, changing consumer preferences and habits, industrialization and new technologies, emergencies, climate change and extreme weather events—are increasing foodborne health risks. Driven by consumer demand, people now have greater access to a wider variety of foods, produced out of season, transported across continents, processed for their convenience and increasingly eaten outside the home. A failure in food safety at any link in the long and complex food chain—from the environment, through primary production, processing, transport, storage, catering or at home—can have significant health and economic consequences, which are augmented by the fact that contamination from a single source may become widespread and have international ramifications (WHO Regional Office for Europe 2015). Dr. Chan points out: ‘‘A local food safety problem can rapidly become an international emergency. Investigation of an outbreak of foodborne disease is vastly more complicated when a single plate or package of food contains ingredients from multiple countries’’ (WHO 2015a). The increasing public health concern over antimicrobial resistance is also a food-safety issue that must be addressed (Kruse and Racioppi 2011; WHO 2015c). Antibiotic use in food animals—for treatment, disease prevention or growth promotion—is considered to spread resistant bacteria and resistance genes from food animals to humans through the food-chain (Kruse and Racioppi 2011). Current surveillance and reporting systems for foodborne disease are limited and detect only a small fraction of cases. This underreporting is greater in countries with less advanced laboratory capacities and less developed surveillance systems. Better data and improved information-sharing are needed to respond effectively to risks (WHO Regional Office for Europe 2015). In an increasingly interconnected world, international collaboration and information-sharing is & Hilde Kruse HIK@euro.who.int

A collaborative initiative for the containment of antimicrobial resistance in Mexico.

Antimicrobial resistance exacts worldwide an increasingly significant clinical and economic toll. Despite the international calls for urgent action, antimicrobial use and resistance have been low on the Mexican government's policy agenda. In early 2010, a multidisciplinary group of experts launched a national initiative for containment of antimicrobial resistance that was endorsed by major medical, veterinary and public health institutions. The initiative called for seven priority actions including the creation of an ad hoc intersectoral advisory group, a requirement that human and veterinary antibiotics be dispensed only with prescription, and the establishment of effective surveillance systems. A consensus document was disseminated among key decision-makers at the ministries of Health and Agriculture and the legislature. The Ministry of Health (MoH) enacted a decree effective as of August 2010, which enforced the regulations that required medical prescriptions for the sale of human antibiotics. While the information disseminated by the MoH did focus on the dangers of self-medication, it failed to highlight the inherent perils of antibiotic resistance or the consequences of antibiotic use in food-animals. Following the decree, there was a surge of medical offices controlled by retail pharmacies. In the veterinary sector, voluntary guidelines were developed for good husbandry practices, including antibiotic use in food animals; five antimicrobials for use in food-animals were banned. No intersectoral advisory group or surveillance systems were established. This study describes a bottom-top approach in Mexico for the development of a national strategy to improve antibiotic use and contain antimicrobial resistance. Its experiences suggest that, in countries such as Mexico that lack strong regulatory systems and surveillance capacities, a more systemic approach is warranted. Future efforts should begin with early involvement of key stakeholders and informing policy makers, professionals and the population at large about the critical importance of antibiotic resistance.

Superbugs: the ever growing threat in our food supply

Dear Editor, Antibiotic resistance is rapidly rising. Many bacterial infections are now very difficult, and sometimes impossible, to treat. Gram negative bacteria are the pointy end of this growing problem, including very common bacteria such as E. coli. Antibiotic resistance is proportional to use. The more antibiotics used, the more resistance develops and spreads. This is both in individuals (e.g. with pneumococcus) and for populations in different countries. With many common bacteria, transmission is almost entirely human-to-human (e.g. pneumococcus, gonococcus, meningococcus). Thus, any antibiotic resistance seen in these bacteria will be almost entirely due to antibiotics used in the human sector. However with some other bacteria, the resistance seen is almost entirely due to what has occurred in the agriculture sector. Examples are non-typhoid salmonella and campylobacter. In developed countries these bacteria are almost entirely acquired from food animals (via foods). These are zoonoses, and thus almost all the antibiotic resistance is a result of what happens with antibiotic use in food animals. Vegetarians are also at risk because water, food crops and fields (via manure) can be contaminated with resistant bacteria. There is also the additional chance of cross contamination of non-meat products from meats along the food chain. There are other bacteria where the risk of acquisition from animal sources is more difficult to precisely define, but appears to be quite important. Examples are E. coli and Enterococcus. We also sometimes get surprises. Until recently Staphylococcus aureus and MRSA were thought to be almost fairly exclusive human pathogens. However, in many countries (e.g. The Netherlands and Denmark), MRSA is now found frequently in pigs and these strains infect people. Clostridium difficile is now clearly associated with food animals and people are infected with strains found in these animals. There are increasing numbers of people with community onsetC. difficile infections. Foods are a likelyway these bacterial strains were acquired. Resistant E. coli are a major concern because E. coli is the most commonbacterial pathogen causing serious infections in people. Bloodstream infection rates vary from 25–60 per 100 000 people per year.This is just the tip of the iceberg, for every such serious and life threatening bloodstream infection, there are likely to be about a hundred other infections (e.g. urinary tract infections).What is nowvery disconcerting is the increasingmulti-resistance resistanceworldwide inE. coli. Much of this resistance in E. coli (especially to third generation cephalosporins and fluoroquinolones) is related to resistance that develops in bacteria carried by food animals – especially poultry. This resistance results from the misuse of antibiotics in these animals. Worldwide each year, billions of chicken are injected with third generation cephalosporins just before or after hatching (with ceftiofur) and/or fed fluoroquinolones in their drinking water (e.g. enrofloxacin) for nearly all their lives. Antibiotics have been used for over 60 years as growth promoters. They are also used for prophylaxis (called ‘metaphylaxis’when large numbers of animals or entire herds are treated at the same time). This is in stark contrast to what happens in human medicine, where individual patient use is the norm. It effectively means that huge numbers of animals are treated continuously for most of their life with either in-feed or in-water antibiotics. It explains why over 70% of all antibiotics used in most countries are used in food animals. Some of these prophylactic antibiotics are last-line or ‘critically important’ classes of antibiotics for humans, such as the fluoroquinolones and third and fourth generation cephalosporins. While there is ongoing debate on what proportion of antibiotic resistant bacteria infecting people come from food animals, it appears to be substantial. An example of where good practice can help people with serious infections is Australia. It is the only country that has banned the use of fluoroquinolones in food animals. It is not coincidental that Australia has also one of the lowest resistance rates in campylobacter, salmonella and E. coli to fluoroquinolones in the world.

Chloramphenicol Use and Prevalence of its Residues in Broiler Chickens and Eggs in Ibadan, Nigeria

Antibiotic use in poultry could result in deposition of residues in edible products of which chloramphenicol is of particular concern because its toxicity and non-dose dependent fatal aplastic anemia in humans. This study assessed the use of antibiotic in poultry production, determined the prevalence and concentration of chloramphenicol residues in meat and eggs from poultry farms and commercial outlets in Ibadan. Semi-structured questionnaires were administered to 75 poultry farmers to assess the use of antibiotics in poultry and the presence of chloramphenicol in chicken eggs and meat randomly obtained from broiler farms and commercial egg outlets were screened for chloramphenicol residues using ELISA technique. The results showed that 50% of the farmers reported administering chloramphenicol to their flocks. Also the survey of five veterinary drugs retail outlets revealed four brands of antibiotics sold for poultry use containing chloramphenicol as an active ingredient. The residue was detected in 51.1% of poultry organs and 25.4% of eggs with mean concentration ranged from 61.8 to 74.6 ng kg -1 in meat and 283.5 to 298.9 ng kg -1 in eggs. The prevalence of chloramphenicol residue was significantly higher in organs than in eggs, but the concentrations were significantly higher in eggs than in meat ( p <0.05). This study documented widespread sales and use of chloramphenicol in poultry in Ibadan with high concentrations of chloramphenicol residues posing public health risks and international trade barrier. We recommend prudent antibiotic use in food animals, alternative treatment regimens and enforcement of appropriate regulatory efforts to prohibit the use of chloramphenicol in food animals. Keywords : Antibiotics, Chloramphenicol Residues, Poultry

A Review of Antibiotic Use in Food Animals: Perspective, Policy, and Potential

Antibiotic use plays a major role in the emerging public health crisis of antibiotic resistance. Although the majority of antibiotic use occurs in agricultural settings, relatively little attention has been paid to how antibiotic use in farm animals contributes to the overall problem of antibiotic resistance. The aim of this review is to summarize literature on the role of antibiotics in the development of resistance and its risk to human health. We searched multiple databases to identify major lines of argument supporting the role of agricultural antibiotic use in the development of resistance and to summarize existing regulatory and policy documents. Several lines of reasoning support the conclusion that agricultural antibiotics are associated with resistance, yet most public policy is based on expert opinion and consensus. Finally, we propose strategies to address current gaps in knowledge.

Thermal Inactivation D- and z-Values of Multidrug-Resistant and Non–Multidrug-Resistant Salmonella Serotypes and Survival in Ground Beef Exposed to Consumer-Style Cooking

There has been speculation that multidrug-resistant (MDR) strains are generated by subtherapeutic antibiotic use in food animals and that such strains result in increased resistance to lethality by food processes such as heat and irradiation. The objective of this study was to evaluate the heat resistance of 20 strains, namely an MDR and a non–multidrug-resistant (NMDR) strain of each of 10 Salmonella serotypes isolated from cattle or cattle environments. MDR and NMDR Salmonella serotypes studied included Montevideo, Typhimurium, Anatum, Muenster, Newport, Mbandaka, Dublin, Reading, Agona, and Give. For phase I, stationary-phase cultures of the strains were aliquoted into sterile capillary tubes and immersed in a temperature-controlled water bath at 55, 60, 65, and 70°C for appropriate times. Survivor curves were plotted for each temperature, and a best-fit linear regression was derived for each temperature. D-values (decimal reduction times) and z-values (changes in temperature required to change the D-values) were calculated for each strain. Although there was no overall significant difference in the heat resistance of MDR and NMDR serotypes, NMDR serotypes generally appeared to have slightly higher heat resistance than NMDR serotypes, especially at 55 and 60°C. The highest relative heat resistance (highest z-values) was exhibited by Salmonella Anatum. Notably, the relative heat resistance of NMDR Salmonella Agona was similar to that of NMDR Salmonella Anatum and had the highest D-values at all four temperatures. For phase II, three serotypes (regardless of resistance profile) with the highest relative heat resistance and their drug-resistant counterparts were selected for thermal inactivation in ground beef patties cooked to endpoint temperatures. Salmonella Agona was able to survive in ground beef cooked to an internal temperature of 71°C. Results of these studies suggest drug resistance does not affect the heat resistance of Salmonella and that serotype or strain is an important consideration in risk assessment of the pathogen with regard to survival at cooking temperatures.

Farm Pens and Prescription Pads

Physicians and medical centers are the front lines of the battle against antibiotic resistance in infectious bacteria. Government agencies, professional organizations, and health care corporations have developed various directives and control mechanisms to help guide physicians toward prescribing practices that minimize the development and dissemination of antibiotic resistance. But as Jeffrey Ritterman, MD, points out in “Preventing Antibiotic Resistance: The Next Step,” (page 35) the quantity of antibiotics routinely administered to livestock and poultry as feed additives appears to dwarf human use. The evidence that using antibiotics as feed additives contributes significantly to the problem of antibiotic resistance in humans has been acknowledged by the major medical associations, including the American Medical Association, American Academy of Family Physicians, American Academy of Pediatrics, and dozens of others, leading them to call for an end to this practice. No economic sector is as directly affected by the challenge of antibiotic resistance as the health care sector. Physicians have taken many necessary steps to curtail unnecessary uses of antibiotics in humans, but what can they do about antibiotic practices on farms? Plenty. Doctors provide a trusted, authoritative voice to the public. Greater awareness of this misuse among physicians can translate into greater awareness and concern among their patients. And an educated, mobilized public can help counter industry denial and government inaction. Just as important is the role physicians play as leaders within medical centers and other large health care institutions. Medical centers have an impact on society that goes well beyond the health services they provide. They are universally among the largest employers in any given region: Kaiser Permanente (KP), as an example, has been the largest private sector employer in Los Angeles County for the past three years. Over the past decade, medical centers have recognized their significant role and responsibility in broader environmental and societal issues through organizations like Health Care Without Harm (HCWH) and Hospitals for a Healthy Environment (H2E). These organizations are reducing the health care industry's environmental footprint and changing markets by getting medical centers to adopt standards and purchasing policies to minimize use of toxic materials, such as mercury. With 140,000 employees, 30 medical centers and over 8 million enrolled patients, KP's actions and policies will influence the nation's economy. And among health care institutions, KP is known as a pioneering leader. KP's adoption of a purchasing policy that minimizes use of antibiotics in agriculture would help educate other hospitals, food services, and members of the public about the need to take similar steps. The adoption of purchasing policies that curtail antibiotic overuse in food animals—notably use of medically important antibiotics as feed additives—is already affecting the market. Environmental Defense has helped McDonald's (the world's largest meat purchaser), as well as Compass America and Bon Appetit (two of the nation's largest food-service companies) craft policies that restrict certain antibiotic uses in chicken. The Compass America policy also addresses the use of antibiotic feed additives in pork.2 While these policies are only first steps, they are having some real impacts. Indeed, earlier this year USA Today1 reported that several of the nation's largest chicken producers had dramatically cut their overall antibiotic use; Tyson's reported a drop of 93%. However, it's not clear to what extent similar steps have been taken throughout the chicken industry, and there is still much to be done in reducing antibiotic use in pork, cattle, and other food animals. It's possible that we are approaching a tipping point on this issue, but we are not there yet. Moreover, there are no regulatory or legislative guarantees that any of the progress made so far in reducing nonessential antibiotic use will be maintained. This is why it's so important for the medical profession and the health care sector to put their money where their mouths are, so to speak, and join these major food companies in setting purchasing policies to move the market away from routine uses of antibiotics in food animals. No economic sector is as directly affected by the challenge of antibiotic resistance as the health care sector. And no other sector's action has the same authority and influence on this issue. As comedian Marty Feldman has said, “the pen is mightier than the sword and much easier to write with.” Physicians, while restraining their pens from writing unnecessary antibiotic prescriptions, should employ them to help move the food industry away from unnecessary antibiotic use in food animals.

Risks of Antibiotic Use in Food Animals

Antibiotic use in food animals results in people being infected with antibiotic-resistant bacteria (WHO 1st Joint FAO/OIE/WHO Expert Workshop on Non-human Antimicrobial Usage and Antimicrobial Resistance: Scientific assessment, Geneva, 1–5 December 2003, http://www.who.int/foodsafety/micro/meetings/nov2003/en/). The recent article by Hurd (Microbe, March 2006, p. 115–119), however, gives an unrealistically low estimate on the risk to people from macrolide use in food animals in the U.S. (1 in 10 million per year). Hurd presents little data in his article, and thus readers can't assess how he arrived at his estimate. Data is available in his prior publication (H. S. Hurd et al., J. Food Prot. 67:980–992, 2004), but his assumptions appear frequently to underestimate likely risks (P. Collignon, J. Food Prot. 67:2369–2370, 2004; L. Tollefson et al., J. Food Prot. 67:2368–2369, 2004).

Assessing Risks to Human Health from Antibiotic Use in Food Animals

For many years, various experts and organizations have said that using antibiotics to raise food animals poses a significant public health risk. The hypothesized threat is the potential development of antibiotic resistance in foodborne bacteria, including pathogens that could infect humans, which could lead to averse effects if these ill people are treated with the same class of antibiotic. However, other experts and groups contend that the public health risks are negligible.

Role of veterinary medicine in public health: antibiotic use in food animals and humans and the effect on evolution of antibacterial resistance.

Veterinary public health is another frontier in the fight against human disease. The veterinary public health scope includes the control and eradication of zoonoses, diseases that are naturally transmitted between vertebrate animals and man. These diseases pose a continuous hazard to the health and welfare of the public. More than 100 diseases are categorized as zoonoses, including salmonellosis. It is important to understand how antibiotics are used in humans and in food animals and how these uses affect the evolution of antibacterial resistance. Appropriate use of antibiotics for food animals will preserve the long-term efficacy of existing antibiotics, support animal health and welfare, and limit the risk of transfer of antibiotic resistance to humans. An understanding of the epidemiology of antimicrobial resistance allows development of preventive strategies to limit existing resistance and to avoid emergence of new strains of resistant bacteria. Risk assessments are being used by the Center for Veterinary Medicine at the U.S. Food and Drug Administration as regulatory tools to assess potential risk to humans resulting from antibiotic use in food-producing animals and to then develop microbial safety policies to protect the public health. The veterinary public health scope, in addition to the control and eradication of zoonoses, also includes the development and supervision of food hygiene practices, laboratory and research activities, and education of the public. Thus, it may be seen that there are many ways in which veterinary medicine plays a very important role in public health.