How Do Livestock Animals Become Immune To A Certain Antibiotics
Public Health Rep. 2012 Jan-February; 127(ane): 4–22.
A Review of Antibiotic Apply in Food Animals: Perspective, Policy, and Potential
Timothy F. Landers
aThe Ohio State University, College of Nursing, Columbus, OH
Bevin Cohen
bHeart for Interdisciplinary Research to Reduce Antibody Resistance, Columbia University Schoolhouse of Nursing, New York, NY
Thomas Eastward. Wittum
cThe Ohio Land University, Department of Veterinary Preventive Medicine, Columbus, OH
Elaine L. Larson
bCenter for Interdisciplinary Research to Reduce Antibody Resistance, Columbia University School of Nursing, New York, NY
SYNOPSIS
Antibiotic use plays a major function in the emerging public health crisis of antibiotic resistance. Although the majority of antibody use occurs in agricultural settings, relatively lilliputian attention has been paid to how antibiotic apply in farm animals contributes to the overall problem of antibiotic resistance. The aim of this review is to summarize literature on the office of antibiotics in the development of resistance and its take chances to human health. We searched multiple databases to identify major lines of argument supporting the role of agronomical antibody employ in the evolution of resistance and to summarize existing regulatory and policy documents. Several lines of reasoning support the determination that agronomical antibiotics are associated with resistance, yet nearly public policy is based on expert opinion and consensus. Finally, we propose strategies to address electric current gaps in noesis.
Antibiotic resistance is a looming public health crisis. While once believed to be the province of hospitals and other health-care facilities, a host of community factors are now known to promote antibiotic resistance, and community-associated resistant strains have now been implicated as the cause of many hospital-acquired infections.1 , 2 An inherent consequence of exposure to antibiotic compounds, antibiotic resistance arises as a result of natural selection.three Due to normal genetic variation in bacterial populations, individual organisms may acquit mutations that render antibiotics ineffective, conveying a survival advantage to the mutated strain. In the presence of antibiotics, advantageous mutations can also be transferred via plasmid exchange within the bacterial colony, resulting in proliferation of the resistance trait.4 The emergence of drug resistance has been observed post-obit the introduction of each new class of antibiotics, and the threat is compounded by a slow drug evolution pipeline and limited investment in the discovery and development of new antibiotic agents.5 – 7
International, national, and local antibiotic stewardship campaigns accept been developed to encourage prudent apply of and limit unnecessary exposure to antibiotics, with the ultimate goal of preserving their effectiveness for serious and life-threatening infections.8 , ix In practice, however, clinicians must balance the utilitarian goal of preserving the effectiveness of antibiotics with upstanding obligations to patients who present with conditions that are unlikely to be harmed and may benefit from antibiotic use. In that location is besides considerable debate in veterinarian medicine regarding utilize of antibiotics in animals raised for man consumption (nutrient animals). The potential threat to human health resulting from inappropriate antibiotic utilise in nutrient animals is significant, equally pathogenic-resistant organisms propagated in these livestock are poised to enter the food supply and could exist widely disseminated in nutrient products.10 – 15 Commensal bacteria found in livestock are frequently present in fresh meat products and may serve every bit reservoirs for resistant genes that could potentially be transferred to pathogenic organisms in humans.16 , 17
While antibiotic employ in food animals may stand for a take a chance to human health, the degree and relative impact have not been well characterized. Given divergent stakeholder interests and inadequate enquiry to date, public policy discussions of this issue are often contentious and highly polarized. The aim of this review is to examine the telescopic and nature of antibiotic use in nutrient animals and summarize its potential touch on on human health. Nosotros also review primal national and international policies on apply of antibiotics in food animals. Finally, we propose futurity directions for enquiry and monitoring of the agricultural utilise of antibiotics.
METHODS
Nosotros searched three online databases of medical and scientific literature citations—the National Library of Medicine'due south MEDLINE®, the U.Due south. Department of Agriculture'southward National Agricultural Library Catalog (known as AGRICOLA), and Thomson Reuter's Web of Science—for English-language documents from 1994–2009 containing the keywords "antibody," "antibiotic resistance," "antimicrobial," "antimicrobial resistance," "agronomics," "livestock," "food beast," "subcontract animal," "sus scrofa," "swine," "cattle," "moo-cow," "poultry," and "chicken." Two authors reviewed the references and selected exemplary original research articles examining the clan between antibiotic use in nutrient animals and antibiotic-resistant bacteria in humans. We as well performed searches of the ROAR Commensal Literature Database (part of the Reservoirs of Antibody Resistance [ROAR] project, coordinated by the Alliance for Prudent Use of Antibiotics and funded by a grant from the National Institute of Allergy and Infectious Diseases) and the Earth Health Organization (WHO) website to place research articles and policy documents pertaining to antibiotic use in food animals. An online search engine was used to locate policy statements published by governmental agencies.
RESULTS
In our review, we found that the use of antibiotics in food animals is widespread, yet poorly characterized. Furthermore, in existing studies, neither the risks to human health nor the benefits to animal production take been well studied. Nosotros also found a lack of consistency in national and international policies.
In the post-obit sections, we review the current literature on the nature and scope of antibiotic utilize in food animals, and on the epidemiologic links betwixt use of antibiotics in food animals and resistance in humans. We and then provide an overview of the circuitous adventure analysis framework required to empathize this problem. Finally, we review key national and international policy and regulatory recommendations.
Literature on the nature and telescopic of antibiotic employ in food animals
The high population density of modern intensively managed livestock operations results in sharing of both commensal flora and pathogens, which tin be conducive to rapid dissemination of infectious agents. As a upshot, livestock in these environments commonly require aggressive infection management strategies, which ofttimes include the use of antibody therapy.
Antibiotics are used in food animals to care for clinical disease, to prevent and control common affliction events, and to enhance fauna growth.xviii The different applications of antibiotics in nutrient animals have been described as therapeutic use, safety use, and subtherapeutic use. Antibiotics can be used to care for a single brute with clinical affliction or a large grouping of animals. Nonetheless, these various uses are frequently indistinct; definitions of each blazon of use vary, and the approaches are often practical concurrently in livestock populations.19 For example, 16% of all lactating dairy cows in the U.South. receive antibody therapy for clinical mastitis each year, but nearly all dairy cows receive intramammary infusions of prophylactic doses of antibiotics following each lactation to prevent and control time to come mastitis—primarily with penicillins, cephalosporins, or other beta-lactam drugs.xx Similarly, 15% of beef calves that enter feedlots receive antibiotics for the treatment of clinical respiratory disease, but therapeutic antibiotic doses are as well administered to ten% of apparently healthy calves to mitigate anticipated outbreaks of respiratory affliction.21 Forty-two percentage of beef calves in feedlots are fed tylosin—a veterinarian macrolide drug—to prevent liver abscesses that negatively touch on growth, and approximately 88% of growing swine in the U.South. receive antibiotics in their feed for disease prevention and growth promotion purposes, commonly tetracyclines or tylosin.22 Most antibiotic use in livestock requires a veterinary prescription, although individual treatment decisions are often made and administered by lay subcontract workers in accord with guidelines provided by a veterinary.23 , 24
Despite the widespread adoption of antibiotic use in nutrient animals, reliable data nigh the quantity and patterns of utilise (e.g., dose and frequency) are not available.25 Quantifying antibiotic apply in food animals is challenging due to variations in study objectives—investigators may measure only therapeutic uses, simply nontherapeutic uses, or a combination thereof, depending on their upshot of interest—and lack of clarity surrounding the definitions of therapeutic vs. nontherapeutic uses.26 Although limited, the bachelor data suggest that food animal production is responsible for a meaning proportion of antibody use. In 1989, the Institute of Medicine estimated that approximately half of the 31.9 million pounds of antimicrobials consumed in the U.S. were for nontherapeutic use in animals.27 More recent estimates past the Union of Concerned Scientists, an advocacy grouping that supports reduced agricultural antimicrobial use, suggest that 24.6 million pounds of antimicrobials are used for nontherapeutic purposes in chickens, cattle, and swine, compared with just three.0 1000000 pounds used for human medicine. Calculations by the pharmaceutical manufacture-sponsored Animal Health Institute are more conservative, suggesting that of 17.eight meg pounds of antimicrobials used for animals, just iii.i million pounds are used nontherapeutically.26 Twelve classes of antimicrobials—arsenicals, polypeptides, glycolipids, tetracyclines, elfamycins, macrolides, lincosamides, polyethers, beta-lactams, quinoxalines, streptogramins, and sulfonamides—may be used at unlike times in the life wheel of poultry, cattle, and swine.25 While some of the antimicrobials used in animals are not currently used to treat homo disease, many, such as tetracyclines, penicillins, and sulfonamides, are also used in the treatment of infections in humans.26 The WHO has developed criteria for the classification of antibiotics equally "critically important," "highly of import," and "important" based on their importance in the handling of human illness.28 , 29
All the same, other classes of antimicrobials used in agriculture have not led to concerns nigh dissemination of resistance in humans. For example, some of the most oftentimes used antibiotics in ruminants are ionophores, a distinctive class of antibiotics that alter abdominal flora to attain increased energy and amino acrid availability and improved food utilization. Almost beef calves in feedlots and some dairy heifers receive this drug routinely in their feed. Because of their specific mode of activity, ionophores have never been used in humans or therapeutically in animals. While some bacteria are intrinsically resistant to these drugs, there is currently no evidence to suggest that ionophore resistance is transferable or that co-option for resistance to other classes of antimicrobials occurs.xxx
Literature suggesting epidemiologic evidence of an association between antibiotic employ in food animals and antibiotic resistance in humans
Prove that antibiotic employ in nutrient animals can result in antibiotic-resistant infections in humans has existed for several decades. Associations betwixt antibiotic use in food animals and the prevalence of antibiotic-resistant bacteria isolated from those animals have been detected in observational studies as well as in randomized trials. Antibody-resistant bacteria of fauna origin have been observed in the environment surrounding livestock farming operations, on meat products available for purchase in retail food stores, and as the cause of clinical infections and subclinical colonization in humans. Figure ane outlines a sampling of prevalence studies, outbreak investigations, ecological studies, case-command studies, and randomized trials whose results suggest a potential relationship between antibiotic utilise in food animals and antibiotic resistance in humans.
Literature on the risks and benefits of antibody use in food animals
To understand how antibiotic employ in agronomics might bear upon the emergence of antibiotic resistance, it is essential to consider the complex interaction of elements in the physical surround (east.one thousand., air, soil, and h2o) with social exchanges (e.g., between animals inside a herd, farmers and animals, and domestic poultry and migratory birds), in processing steps (e.chiliad., farming activities, transportation, and storage), and in human employ patterns (eastward.yard., food preparation, meat consumption, and susceptibility to infection) (Effigy 2). Antibiotic utilise in animals tin have direct and indirect effects on human health: straight effects are those that can be causally linked to contact with antibiotic-resistant bacteria from nutrient animals, and indirect furnishings are those that result from contact with resistant organisms that accept been spread to various components of the ecosystem (east.g., water and soil) as a result of antibiotic utilize in nutrient animals (Figure three).
Figure 3.
Examples of directly and indirect effects of antibiotic use in food animals on human health
Given the multitude of factors that contribute to the pathways past which antibiotic use in nutrient animals could pose risks to human health, it is not surprising that a broad variety of methods has been used by researchers in various disciplines to arroyo the problem. In general, risk assessment models in veterinarian medicine emphasize animal wellness and handling of diseases in animals, food scientists' studies focus on the safety of human food supplies and the presence of antibiotic-resistant bacteria on nutrient products, clinicians and epidemiologists investigate man outbreaks acquired past resistant infections for which animals are identified as primary sources, and molecular biologists examine relationships between resistant strains and the prevalence of specific resistance genes in human being and animal leaner. It is unlikely that whatsoever single study will be able to fully and accurately quantify the human relationship betwixt antibiotic use in food animals and infections in humans. At best, only crude estimates of the etiologic fraction or "bear upon fraction" can be made for specific links in the ecologic chain.31
Several mathematical models have been proposed to quantify the overall take a chance associated with antibiotic employ in animals, typically by estimating the prevalence of infection with a specific organism and its associated morbidity, and and so multiplying by the proportion of these infections believed to exist attributable to antibiotic use in food animals. While models of this nature have been rightfully criticized for declining to include indirect take chances and, consequently, underestimating total potential risk, felicitous take a chance assessment strategies must also consider the potential benefits of antibiotic use in food animals. Fifty-fifty though agricultural antibody use carries a demonstrated take a chance, at that place are probable benefits to the agricultural utilize of antibiotics too. For example, reducing beast microbial load and shedding could lead to safer, more than affordable nutrient. All the same, many of the claims of do good accept not been fully demonstrated in big-scale trials, and other trials have shown that the overall bear on of the brusque-term benefit is poorly described.
The U.South. Food and Drug Administration (FDA) requires manufacturers of new antibiotics to perform risk assessments to demonstrate that new drugs are safe and constructive for utilize in animals and that "there is reasonable certainty of no damage to human health from the proposed use of the drug in food-producing animals."32 To evaluate potential human health consequences, the FDA employs a qualitative framework to classify as "low," "medium," or "high" the probabilities that bacteria in the animal population will acquire resistance, that humans volition ingest the resistant bacteria in nutrient products, and that ingesting the bacteria will consequence in agin health outcomes (Figure four). Drug approval decisions are based on these take a chance estimations, forth with information about proposed marketing status (e.m., prescription, over-the-counter, or veterinary feed additives), extent of limitations on actress-label utilize, and intended use patterns (e.one thousand., elapsing of use and administration to individual animals vs. select groups of animals vs. flocks or herds of animals). "High-chance" drugs may be canonical if the FDA determines that human being health gamble tin can be mitigated. "Medium-risk" drugs could be approved if appropriate characterization restrictions are required.
In improver to the direct risk assessment model, the FDA has adult guidance to determine the hazard of antibody residues remaining on nutrient products.32 This guidance recommends determining the impact of antibiotic residues on normal human abdominal flora and the presence of resistance in these strains, and it provides guidelines for the calculation of Acceptable Daily Intake (ADI) for antibiotic residues that pose an observable risk to human health.
Guidelines and recommendations on the utilize of antibiotics in food animals
Given the importance of antibiotic resistance as a public wellness problem, many governments and professional societies accept reviewed existing scientific show and developed recommendations to limit all types of antibody employ, including employ in food animals. Depending on the nature and jurisdiction of each group, the findings may provide best practice guidelines for antibiotic utilise, prioritized agendas for research on the emergence of antibiotic resistance, recommendations for legislative action to regulate drug approving and surveillance processes, or enforceable laws on the manufacture, distribution, and prescription of antibiotics. Figure v summarizes recommendations straight related to employ of antibiotics in food brute production for a sample of national and international guidance and policy documents.
DISCUSSION
Despite increasingly widespread recognition that antibiotic use in nutrient animals is an important contributor to human being infections with antibody-resistant bacteria (Effigy 1), there remains a significant need for scientific evidence of the antibody utilise practices that create the greatest homo health risk. Our goal with this article was not to propose specific solutions to the problem—in role because we believe there are no easy, specific answers—but rather to reiterate and summarize the importance of this event and to suggest some general policy directions that are indicated. As the importance of the trouble and complexity of the issues are increasingly appreciated by the public, policy dialogue, focused research, and informed regulatory action can be undertaken. To facilitate further research and timely action in response to emerging knowledge on this issue, we propose the post-obit measures, which are in concert with WHO's global strategy for the containment of antimicrobial resistance, the U.S. Interagency Task Force on Antibiotic Resistance's public wellness activity plan to combat antimicrobial resistance, and the Infectious Diseases Social club of America's call to action.33 – 35
Develop a scientific calendar to recommend appropriate study designs and specific aims related to antimicrobial use in food animals
A coordinated plan is needed to identify missing scientific data and to specify research designs and methods to accost these needs. Although rigorous studies have been conducted in some disciplines, there has been a lack of serious and harmonized interdisciplinary effort to expand on the corpus of knowledge, which should be used to inform public policy. To result in a useful and consummate listing of inquiry priorities, the agenda must include contributions past experts in basic sciences (e.g., genetics and microbiology), clinical sciences (e.g., veterinarian medicine and human medicine), public health (e.m., epidemiology and nursing), social sciences (eastward.one thousand., anthropology and sociology), economic science (e.g., wellness and agronomics), and public policy (e.g., legislative and regulatory). Inquiry goals put forth in the agenda should be reflective of methodological weaknesses identified in the existing literature. For case, definitions of antibiotic uses in food animals (e.g., therapeutic and subtherapeutic) should be standardized and designed to reflect specific goals (e.g., improving production or preventing economic loss from unrestrained affliction); the terms should be recognized beyond disciplines and used to allocate the potential effects of different types of antibiotic use on human health. Some other potential focus could exist whether to arroyo research on the evolution of resistance narrowly (i.e., the causes and furnishings of specific drug-organism combinations) or broadly (i.due east., the causes and effects of all antibiotics used in animals on microbial flora) to develop public health recommendations.
Fund agricultural inquiry that reflects the priorities identified by the research agenda
Inadequate funding for agronomical research has likely contributed to the lack of sufficient scientific evidence necessary for informing public health decisions. For example, in the U.s., it was recently estimated that the $101 billion in combined governmental and biomedical industry inquiry funding represents near 5% of national health expenditures each year.36 In 2007, the U.S. Section of Agronomics provided more than $32 1000000 in external inquiry funding, representing less than one one-thousandth of 1% of annual U.S. livestock and poultry sales.37 In contrast, one single Institute within the National Institutes of Health—the National Institute of Allergy and Infectious Diseases—directed more than 20 times this amount to antimicrobial resistance research (more $800 million) in the same yr.38 Given the scale of the antibody resistance problem and the demonstrated role of agricultural antibiotic uses in this impending public wellness crisis, adequate back up for inquiry specific to the role of agricultural uses of antibiotics in the development of resistance must be a national priority. Considering that the U.Southward. funds 70% to 80% of biomedical research worldwide, the need for appropriate levels of funding is specially acute.36
Urgently address barriers to the drove and analysis of antimicrobial use data
Complex political, economic, and social barriers limit the quality of data on the use of antibiotics in food animals. Currently, such data are provided on a voluntary ground, and the methods used to collect and compile reports are non standardized or fully transparent. While voluntary industry compliance with antibiotic reporting is commendable, the long-term effectiveness of nonbinding auditing programs is unproven. Effective surveillance of veterinary antimicrobial product and assistants to food animals is a central first step toward ascertaining realistic estimates of the full scope of antibiotic use. These data will be useless, nevertheless, unless an agency with adequate analytic, regulatory, and enforcement capabilities exists. Because the commercial interests of antibiotic manufacturers must exist appropriately counterbalanced with the public wellness urgency for development of new antibiotics, whatsoever agency tasked with monitoring antibiotic resistance must operate independently of commercial influences when releasing information to the public and drafting prove-based regulations to safeguard human health.
Determination
It is axiomatic that now, the resources devoted to studying the office of antibody use in nutrient animals—both in terms of funding and scientific inquiry—are bereft. It is at present critical that agricultural employ of antibiotics exist recognized as one of the major contributors to the development of resistant organisms that result in life-threatening human infections and included as part of the strategy to control the mounting public health crisis of antibiotic resistance.
Footnotes
During portions of this project, Dr. Landers was supported by a training grant from the National Plant of Nursing Enquiry, National Institutes of Health (Training in Interdisciplinary Enquiry to Reduce Antimicrobial Resistance; T90 NR010824).
REFERENCES
1. Boyce JM. Customs-associated methicillin-resistant Staphylococcus aureus as a cause of health care-associated infection. Clin Infect Dis. 2008;46:795–8. [PubMed] [Google Scholar]
2. Popovich KJ, Weinstein RA. The graying of methicillin-resistant Staphylococcus aureus. Infect Control Hosp Epidemiol. 2009;thirty:9–12. [PubMed] [Google Scholar]
3. Aminov RI, Mackie RI. Evolution and ecology of antibiotic resistance genes. FEMS Microbiol Lett. 2007;271:147–61. [PubMed] [Google Scholar]
4. Courvalin P. Anticipated and unpredictable evolution of antibody resistance. J Intern Med. 2008;264:four–16. [PubMed] [Google Scholar]
five. Spellberg B, Powers JH, Brass EP, Miller LG, Edwards JE., Jr Trends in antimicrobial drug development: implications for the future. Clin Infect Dis. 2004;38:1279–86. [PubMed] [Google Scholar]
6. Talbot GH, Bradley J, Edwards JE, Jr, Gilbert D, Scheld M, Bartlett JG. Bad bugs need drugs: an update on the development pipeline from the Antimicrobial Availability Task Force of the Infectious Diseases Order of America. Clin Infect Dis. 2006;42:657–68. [PubMed] [Google Scholar]
7. Norrby SR, Nord CE, Finch R European Society of Clinical Microbiology and Infectious Diseases. Lack of development of new antimicrobial drugs: a potential serious threat to public health. Lancet Infect Dis. 2005;5:115–ix. [PubMed] [Google Scholar]
eight. Avorn JL, Barrett JF, Davey PG, McEwen SA, O'Brien TF, Levy SB. Geneva: World Health Arrangement; 2001. [cited 2010 Nov x]. Antibiotic resistance: synthesis of recommendations by expert policy groups. Also available from: URL: http://whqlibdoc.who.int/hq/2001/WHO_CDS_CSR_DRS_2001.10.pdf. [Google Scholar]
9. Belongia EA, Knobloch MJ, Kieke BA, Davis JP, Janette C, Besser RE. Impact of statewide program to promote appropriate antimicrobial drug employ. Emerg Infect Dis. 2005;11:912–20. [PMC complimentary commodity] [PubMed] [Google Scholar]
10. Garofalo C, Vignaroli C, Zandri Thousand, Aquilanti L, Bordoni D, Osimani A, et al. Direct detection of antibody resistance genes in specimens of chicken and pork meat. Int J Food Microbiol. 2007;113:75–83. [PubMed] [Google Scholar]
11. Cui S, Ge B, Zheng J, Meng J. Prevalence and antimicrobial resistance of Campylobacter spp. and Salmonella serovars in organic chickens from Maryland retail stores. Appl Environ Microbiol. 2005;71:4108–11. [PMC free article] [PubMed] [Google Scholar]
12. Gundogan Northward, Citak S, Yucel N, Devren A. A note on the incidence and antibiotic resistance of Staphylococcus aureus isolated from meat and chicken samples. Meat Sci. 2005;69:807–ten. [PubMed] [Google Scholar]
13. Kim SH, Wei CI, Tzou YM, An H. Multidrug-resistant Klebsiella pneumoniae isolated from farm environments and retail products in Oklahoma. J Food Prot. 2005;68:2022–9. [PubMed] [Google Scholar]
14. Parveen Due south, Taabodi Thousand, Schwarz JG, Oscar TP, Harter-Dennis J, White DG. Prevalence and antimicrobial resistance of Salmonella recovered from candy poultry. J Food Prot. 2007;seventy:2466–72. [PubMed] [Google Scholar]
xv. Ramchandani Chiliad, Manges AR, DebRoy C, Smith SP, Johnson JR, Riley LW. Possible animal origin of human-associated multidrug-resistant, uropathogenic Escherichia coli. Clin Infect Dis. 2005;40:251–7. [PubMed] [Google Scholar]
xvi. Mena C, Rodrigues D, Silva J, Gibbs P, Teixeira P. Occurrence, identification, and label of Campylobacter species isolated from Portuguese poultry samples collected from retail establishments. Poult Sci. 2008;87:187–90. [PubMed] [Google Scholar]
17. Diarrassouba F, Diarra MS, Bach Southward, Delaquis P, Pritchard J, Topp Eastward, et al. Antibiotic resistance and virulence genes in commensal Escherichia coli and Salmonella isolates from commercial broiler chicken farms. J Food Prot. 2007;70:1316–27. [PubMed] [Google Scholar]
xviii. McEwen SA, Fedorka-Cray PJ. Antimicrobial use and resistance in animals. Clin Infect Dis. 2002;34(Suppl 3):S93–106. [PubMed] [Google Scholar]
19. Institute of Medicine; National Research Council; Panel on Animal Health, Food Safety and Public Health; Committee on Drug Use in Food Animals. Washington: National University Printing; 1999. The use of drugs in food animals: benefits and risks. [Google Scholar]
20. Department of Agronomics (Us) Fort Collins (CO): USDA, Animal and Institute Health Inspection Service, Veterinary Services, National Animal Health Monitoring Arrangement; 2008. Sep, [cited 2010 November xi]. Dairy 2007 part III: reference of dairy cattle health and management practices in the United States, 2007. Also available from: URL: http://world wide web.aphis.usda.gov/animal_health/nahms/dairy/downloads/dairy07/Dairy07_dr_PartIII_rev.pdf. [Google Scholar]
22. Department of Agronomics (Usa) Fort Collins (CO): USDA, Animal and Constitute Health Inspection Service, Veterinary Services, National Animal Health Monitoring System; 2008. Mar, [cited 2011 Sep 12]. Swine 2006 part 3: reference of swine health, productivity, and general direction in the The states, 2006. Too available from: URL: http://www.aphis.usda.gov/animal_health/nahms/swine/downloads/swine2006/Swine2006_dr_PartIII.pdf. [Google Scholar]
23. Raymond MJ, Wohrle RD, Call DR. Assessment and promotion of judicious antibiotic apply on dairy farms in Washington Country. J Dairy Sci. 2006;89:3228–40. [PubMed] [Google Scholar]
24. Sawant AA, Sordillo LM, Jayaro BM. A survey on antibiotic usage in dairy herds in Pennsylvania. J Dairy Sci. 2005;88:2991–9. [PubMed] [Google Scholar]
25. Sarmah AK, Meyer MT, Boxall AB. A global perspective on the utilise, sales, exposure pathways, occurrence, fate and effects of veterinary antibiotics (VAs) in the environs. Chemosphere. 2006;65:725–59. [PubMed] [Google Scholar]
27. Institute of Medicine. Washington: National Academy Press; 1989. Man wellness risks with the subtherapeutic use of penicillin or tetracyclines in animal feed. [Google Scholar]
28. World Health Organization. Critically important antimicrobials for human medicine: categorization for the development of gamble management strategies to contain antimicrobial resistance due to non-homo antimicrobial utilise. Written report of the Second WHO Practiced Meeting; 29-31 May 2007; Copenhagen. [cited 2010 November 11]. Available from: URL: http://www.who.int/foodborne_disease/resistance/antimicrobials_human.pdf. [Google Scholar]
29. Collingnon P, Powers JH, Chiller TM, Aidara-Kane A, Aarestrup FM. World Health Organisation ranking of antimicrobials co-ordinate to their importance in human being medicine: a critical step for developing risk management strategies for the utilise of antimicrobials in food production animals. Clin Infec Dis. 2009;49:132–41. [PubMed] [Google Scholar]
thirty. Callaway TR, Edrington TS, Rychlik JL, Genovese KJ, Poole TL, Jung YS, et al. Ionophores: their employ every bit ruminant growth promotants and impact on nutrient safety. Curr Issues Intest Microbiol. 2003;4:43–51. [PubMed] [Google Scholar]
31. Greenland S, Rothman KJ, Lash TL. Measures of effect and measures of association. In: Rothman KJ, Greenland S, Lash TL, editors. Modernistic epidemiology. 3rd ed. Philadelphia: Wolters Kluwer/ Lippincott Williams & Wilkins; 2008. pp. 51–lxx. [Google Scholar]
32. Department of Wellness and Human Services (Usa), Food and Drug Administration, Center for Veterinary Medicine. Guidance for industry #152: evaluating the rubber of antimicrobial new animal drugs with regard to their microbiological effects on bacteria of human health concern. 2003. October 23, [cited 2010 Nov eleven]. Available from: URL: http://www.fda.gov/downloads/AnimalVeterinary/-GuidanceComplianceEnforcement/GuidanceforIndustry/UCM052519.pdf.
33. Globe Health Organization. WHO global principles for the containment of antimicrobial resistance in animals intended for food: report of a WHO consultation with the participation of the Food and Agronomics Organization of the United Nations and the Office International des Epizooties, 5–9 Jun 2000, Geneva. [cited 2010 Nov eleven]. Available from: URL: http://whqlibdoc.who.int/hq/2000/who_cds_csr_aph_2000.4.pdf.
34. Interagency Task Force on Antimicrobial Resistance (US) Atlanta: Centers for Disease Control and Prevention (US), Food and Drug Assistants (US), National Institutes of Health; 2008. Jun, [cited 2010 Nov 11]. A public wellness action plan to combat antimicrobial resistance: part 1: domestic issues. Also bachelor from: URL: http://world wide web.cdc.gov/drugresistance/actionplan/aractionplan.pdf. [Google Scholar]
35. Spellberg B, Guidos R, Gilbert D, Bradley J, Boucher HW, Scheld WM, et al. The epidemic of antibiotic-resistant infections: a call to action for the medical customs from the Infectious Diseases Society of America. Clin Infect Dis. 2008;46:155–64. [PubMed] [Google Scholar]
36. Dorsey ER, de Roulet J, Thompson JP, Reminick JI, Thai A, White-Stellato Z, et al. Funding of United states biomedical research, 2003–2008. JAMA. 2010;303:137–43. [PMC free article] [PubMed] [Google Scholar]
37. Roberts RM, Smith GW, Bazer FW, Cibelli J, Seidel GE, Jr, Bauman DE, et al. Research priorities: subcontract beast research in crunch. Science. 2009;324:468–9. [PubMed] [Google Scholar]
38. Peters NK, Dixon DM, Holland SM, Fauci AS. The research agenda of the National Institute of Allergy and Infectious Diseases for antimicrobial resistance. J Infect Dis. 2008;197:1087–93. [PubMed] [Google Scholar]
Articles from Public Health Reports are provided here courtesy of SAGE Publications
Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3234384/
Posted by: owenswhearour.blogspot.com
0 Response to "How Do Livestock Animals Become Immune To A Certain Antibiotics"
Post a Comment