Antibiotic Resistance Monitoring in Food Animals – Essential Component of Responsible Use of Antimicrobials in Veterinary Medicine

New Delhi, March 29, 2016: As we look at addressing the issues of antibiotic resistance in India, under the umbrella of responsible use a number of actions could be implemented including but not limited to (1) Antibiotic resistance monitoring (2) Antibiotic Usage Monitoring (3) Antibiotic Availability by Prescription Only (4) National Formularies and Prescriber Guidelines (5) Consideration of the distribution channel and the promotion of prescription only antibiotics. This article focuses on the first point, Antibiotic Resistance Monitoring.

Antibiotic resistance monitoring forms the corner stone of risk assessment and a metric for measuring risk management policies. Embedded in a microbiological risk assessment to evaluate the potential of antibiotic resistant bacteria contributing to infections in humans that cannot be treated with the same antibiotic class that were used in food animalsare the parameters of release, exposure and consequence. Once a risk assessment identifies a potential risk such as increased prevalence of antibiotic resistance and appropriate risk management is implemented, antimicrobial resistance needs to continue to determine if resistance has decreased post risk management intervention indicating appropriate action vs. resistance levels either increasing or remaining stable which would indicate inappropriate risk management policies.

Zoonotic bacteria such as Salmonella and Campylobacter can develop resistance to antibiotics in the animal reservoir. These resistant bacteria may be transferred to humans via food and may subsequently cause infections that may not respond adequately to antibiotic treatment. Commensal bacterial populations from the intestinal tract of animals may reflect antibiotic selection pressure as a result of use of antibiotics over time. Animal-origin commensals may also act as a reservoir of resistance genes that can be transferred to pathogens or to other commensals in the human gut. For this reason, Escherichia coli and enterococci of animal origin are included in many resistance monitoring programmes as indicator bacteria representative of the Gram-negative and Gram-positive flora, respectively, in order to provide information about the general prevalence of resistance in healthy production animals. These zoonotic and commensal indicator bacteria are referred to as food-borne bacteria in the context of the discussion below.

Resistance monitoring programmes of food-borne bacteria typically collect bacterial strains from food-producing animals, generally at slaughter but also on farm and from retail meats, and then determine their susceptibility against a panel of antibiotics relevant for human medicine. Monitoring of the antimicrobial susceptibility of food-borne bacteria is performed on both a national and international level. Examples of monitoring systems on a regular basis at national level are CIPARS (Canada), DANMAP (Denmark), JVARM (Japan), MARAN (Netherlands), NARMS (USA), NORM-VET (Norway), and SVARM (Sweden). There are a few harmonized international programmes. In the late nineteen nineties, the European Antimicrobial Susceptibility Surveillance in Animals (EASSA) programme was initiated as a shared initiative of the veterinary pharmaceutical industry whilst over a decade ago the European Food Safety Authority (EFSA) established an overarching antimicrobial resistance monitoring programme in food-borne pathogens from food-producing animals and food thereof. The latter integrated EU monitoring has now replaced part of the national programmes in Europe. Hence, currently two international European monitoring programmes of antimicrobial resistance of food-borne bacteria in animals are in place. Additionally, various one-off monitoring studies continue to be published periodically.

Monitoring of antimicrobial resistance currently has a high profile and it is on many international political agendas. Of major concern is the emergence and spread of antimicrobial resistance in bacteria, impeding the adequate treatment of bacterial infections in humans. The potential for transmission of antimicrobial-resistant bacteria or their resistance determinants from food-producing animals to humans has been a public health concern for several decades. It should be noted that most resistance developing in pathogens posing a serious risk to human health, is the result of human application rather than veterinary use of antimicrobials. Multi-drug resistance has developed in pathogens that exclusively infect humans such as Helicobacter pylori, Mycobacterium tuberculosis,Neisseria gonorrhoea,Salmonella typhi and Streptococcus pneumoniae. Food-borne bacteria do not cause the most serious or the most frequent infections with resistant bacteria in humans. The World Health Organization (WHO) considers antimicrobial resistance as an urgent global health threat and has identified various strategies to diminish the threat. The WHO Global Action Plan includes improvements of the quality of resistance monitoring and calls for harmonized and standardized surveillance systems. Antimicrobial resistance monitoring programmes, both in human and veterinary medicine, therefore remain essential to track the emergence of antibiotic resistance. Many organizations including the WHO and World Organization for Animal Health (OIE) emphasize the importance of reliable and harmonized data collection and monitoring systems. Indeed, appropriate and harmonized antibiotic susceptibility methodology and data interpretation are crucial for enabling objective comparisons and risk assessments within and between countries. There are various national veterinary antibiotic susceptibility surveillance systems that are currently undertaken and it is important to emphasize at the outset that all of the reviewed surveillance systems have great merit, especially when considering resistance trends within the countries in which the surveillance has been instigated. Yet internationally there has been little success in attempting to harmonize the respective approaches thus making horizontal comparisons across countries difficult if not impossible.

Authors: Shabbir Simjee – Elanco Animal Health, Basingstoke, United Kingdom & Shraman Jha- Elanco Animal Health, Bangalore, India

Corporate Comm India(CCI Newswire)