Preventing introduction of livestock associated MRSA in a pig population--benefits, costs, and knowledge gaps from the Swedish perspective

Economic Evaluation of Interventions to Reduce Antimicrobial Resistance: A Systematic Literature Review of Methods

BACKGROUND AND OBJECTIVE

Economic evaluation of antimicrobial resistance (AMR) interventions is complicated by the multisectoral, inter-temporal and international aspects of the problem, further hindered by a lack of available data and theoretical understanding of the emergence and transmission of AMR. Despite the substantial global focus on the problem, there is a lack of comprehensive economic evaluation literature on AMR policies. The goal of this work is to review the available literature on the economic evaluation of AMR interventions focusing on methods used to quantify the effects on AMR and the associated health consequences and costs.

METHODS

The studies included in the review were identified by a previous study by Painter et al. that included all full economic evaluations of AMR policies in the peer-reviewed and grey literature published between 2000 and 2020. The current review extracted additional information to (1) summarise the types and the key features of the AMR intervention economic evaluation literature available; (2) systemise the types of intervention effects on AMR quantified and describe these across the dimensions of AMR burden: time, space, wider pathogen pool and different sectors (One Health framework); and (3) categorise the methods used to derive these outcomes and how were these linked to health consequences and costs.

RESULTS

Thirty-one studies were included within this review, of which 18 evaluated interventions that aimed to reduce infection rates and 11 evaluated interventions that aimed to optimise antimicrobial use. Almost all were conducted with a high-income and/or upper-middle income country perspective and focused on human health. Thirteen of 31 studies were cost-utility analyses. Fifteen of 31 and 7/31 studies estimated the AMR effects through decision tree and/or Markov models and transmission models, respectively. Transmission models and linkage of AMR outcomes to quality-adjusted life-years and costs were more common in evaluations of interventions aimed at reducing infection rates. Most of the included studies restricted the scope of evaluation to a short time horizon and a narrow geographical scope and did not consider the wider impact on other pathogens and other settings, potentially resulting in an incomplete capture of the effects of interventions.

CONCLUSIONS

This review found limited available literature that mainly focused on high-income countries and infection prevention/reduction strategies. Most evaluations used a narrow study scope, which might have prevented the full capture of the costs and outcomes associated with interventions. Finally, despite the known complexities associated with quantifying AMR effects, and the corresponding methodological challenges, the implications of these choices were rarely discussed explicitly.

A systematic literature review of economic evaluation studies of interventions impacting antimicrobial resistance

BACKGROUND

Antimicrobial resistance (AMR) is accelerated by widespread and inappropriate use of antimicrobials. Many countries, including those in low- and middle- income contexts, have started implementing interventions to tackle AMR. However, for many interventions there is little or no economic evidence with respect to their cost-effectiveness. To help better understand the scale of this evidence gap, we conducted a systematic literature review to provide a comprehensive summary on the value for money of different interventions affecting AMR.

METHODS

A systematic literature review was conducted of economic evaluations on interventions addressing AMR. a narrative synthesis of findings was produced. Systematic searches for relevant studies were performed across relevant databases and grey literature sources such as unpublished studies, reports, and other relevant documents. All identified economic evaluation studies were included provided that they reported an economic outcome and stated that the analysed intervention aimed to affect AMR or antimicrobial use in the abstract. Studies that reported clinical endpoints alone were excluded. Selection for final inclusion and data extraction was performed by two independent reviewers. A quality assessment of the evidence used in the included studies was also conducted.

RESULTS

28,597 articles were screened and 35 articles were identified that satisfied the inclusion criteria. The review attempted to answer the following questions: (1) What interventions to address AMR have been the subject of an economic evaluation? (2) In what types of setting (e.g. high-income, low-income, regions etc.) have these economic evaluations been focused? (3) Which interventions have been estimated to be cost-effective, and has this result been replicated in other settings/contexts? (4) What economic evaluation methods or techniques have been used to evaluate these interventions? (5) What kind and quality of data has been used in conducting economic evaluations for these interventions?

DISCUSSION

The review is one of the first of its kind, and the most recent, to systematically review the literature on the cost-effectiveness of AMR interventions. This review addresses an important evidence gap in the economics of AMR and can assist AMR researchers' understanding of the state of the economic evaluation literature, and therefore inform future research. Systematic review registration PROSPERO (CRD42020190310).

A review of new emerging livestock-associated methicillin-resistant Staphylococcus aureus from pig farms

Methicillin-resistant Staphylococcus aureus (MRSA) is a S. aureus strain resistant to β-lactam antibiotics and is often associated with livestock, known as livestock-associated (LA)-MRSA. Using molecular typing with multi-locus sequence typing, MRSA clones have been classified in pigs, including clonal complex 398. Livestock-associated-methicillin-resistant S. aureus was first discovered in pigs in the Netherlands in 2005. Since then, it has been widely detected in pigs in other countries. Livestock-associated-methicillin-resistant S. aureus can be transmitted from pigs to pigs, pigs to humans (zoonosis), and humans to humans. This transmission is enabled by several risk factors involved in the pig trade, including the use of antibiotics and zinc, the size and type of the herd, and the pig pen management system. Although LA-MRSA has little impact on the pigs' health, it can be transmitted from pig to pig or from pig to human. This is a serious concern as people in direct contact with pigs are highly predisposed to acquiring LA-MRSA infection. The measures to control LA-MRSA spread in pig farms include conducting periodic LA-MRSA screening tests on pigs and avoiding certain antibiotics in pigs. This study aimed to review the emerging LA-MRSA strains in pig farms.

Costs and Benefits of Alternative Strategies to Control the Spread of Livestock-Acquired Methicillin-Resistant Staphylococcus Aureus From Pig Production

BACKGROUND

Livestock-acquired methicillin-resistant Staphylococcus aureus (LA-MRSA) is a concern in healthcare and a political priority in some countries.

OBJECTIVE

This study investigates the net societal costs of 2 alternative strategies for controlling LA-MRSA in Denmark: (1) eradicating LA-MRSA in all pig housing units, and (2) containing LA-MRSA within the units.

METHODS

Benefits and costs are considered for affected economic sectors: healthcare, pig production, pig-related industries, and public administration.

RESULTS

The cost to society of eradication is estimated at €2.3 to €2.5 billion (present value). Containment will cost €55 to €93 million. For both strategies, the main cost lies in primary pig production-for containment this is mainly due to establishing and operating anterooms and shower rooms, and for eradication it is due to production losses, loss of genetic resources, and costs of cleaning and disinfection.

CONCLUSION

Compared with these costs, health economic benefits are moderate for both strategies. Containment is superior to eradication when measured by a benefit-cost ratio.

One Health as a moral dilemma: Towards a socially responsible zoonotic disease control

During the last decade, the concept of One Health has become the international standard for zoonotic disease control. This call for transdisciplinary collaboration between professionals in human, animal and environmental health has produced several successes in zoonotic disease control, surveillance and research. Despite the lack of a clear definition, a shared agenda or institutional governance, One Health has proven to be a fruitful idea. Due to its ambiguity, the One Health concept functions as a boundary object: by leaving room for interpretation to fit different purposes, it facilitates cooperation. In many cases, this results in the promotion of health of humans, animals and the environment. However, there are also situations in which this mutual benefit of a One Health approach is not that evident, for instance, when healthy animals are culled to protect public health. Although such a strategy could well be part of a One Health approach, it is hard to understand how this contributes to the health of concerning animals. Consequently, these practices often lead to public debate. This raises questions on how we should understand the One Health concept in zoonotic disease control. Is it really about equally improving the health of humans, animals and the environment and is this even possible? Or is it ultimately just public health that counts? In cases of conflict between different values, the lack of a universal definition of the One Health concept contributes to this complexity. Although boundary objects have many positive aspects, in the context of One Health and zoonotic disease control, this conception seems to conceal underlying normative differences. To address moral dilemmas related to a One Health approach in zoonotic disease control, it is important to reflect on moral status and the meaning of health for humans, animals and the environment.

Modeling the cost of eradicating livestock-associated methicillin-resistant staphylococcus aureus in countries with a high proportion of positive herds

Due to an increased incidence of human infections, livestock-associated methicillin-resistant Staphylococcus Aureus (LA-MRSA) in pigs and its spread into the human population has been a major public and political issue in Denmark. Similar concerns are also being raised about LA-MRSA in other Western European countries. At a time when the proportion of LA-MRSA-positive pig farms was low, Norway adopted a 'trace and destroy' strategy aimed at keeping LA-MRSA out of the pig population. However, to date, no country with a high proportion of LA-MRSA-positive pig herds has chosen to use an eradication strategy. This study analyses the cost and complexities of conducting an LA-MRSA eradication program in a situation where a large proportion of herds are positive. The total cost of the eradication program was estimated based on the following components: 1) planning, 2) monitoring and testing, 3) cleaning and disinfection, 4) production gains and losses, 5) net reduction in breeding exports, and 6) loss of genetic progress, including the costs of a mitigating caesarean section strategy in breeding herds. Costs were related to the depopulation of 1 million sows, to gilt supply (as this was an important limiting factor during an eradication program in Denmark), and to aggregated losses linked to a temporary halt on breeding progress. Using conservative assumptions, the total eradication costs were estimated at €1.8 billion, broken down into: planning costs (3%), monitoring and testing (6%), cleaning and disinfection (19%), production gains and losses (33%), net loss from breeding exports (19%) and loss of genetic progress (20%). The long-term effects of an LA-MRSA eradication program for Danish pig production were uncertain and were therefore not taken into account in the analysis.

Why Antibiotic Use Data in Animals Needs to Be Collected and How This Can Be Facilitated

Antimicrobial resistance (AMR) is currently recognized as one of the most significant threats to public health worldwide. It is a phenomenon that highlights the interconnectivity between human and animal health since any use of antibiotics in humans can eventually lead to resistance in the microbial populations colonizing animals and vice versa. In recent years, our understanding of the relationship between the use of antibiotics and the consequent development of resistance in microbial populations to these (or similar) antibiotics has increased. Having accurate data, ideally in a digital format, on the use of antibiotics are therefore of paramount importance. Current obstacles to having such data include, among others, the lack of consensual and harmonized technical methods and units that represent antimicrobial use (AMU), the insufficient incentives to motivate primary producers to report their use of antibiotics, and the inexistence of user-friendly technologies for the collection of such data, despite the generalized use of Internet and electronic devices. Further development and adoption of the units proposed by the European Surveillance of Veterinary Antimicrobial Consumption will contribute to the long-desired harmonization. Rewarding the animal producers (via tax incentives, for example) that use less antibiotics and the development of an app, to which producers could orally report the used antibiotics are among the solutions that could help to overcome the current challenges. I here also argue that having mandatory electronic veterinary prescriptions and awareness campaings, funded via public-private partnerships, should also be considered as methods that could help for the control of societal problems like AMR.