White Paper: Public Health Impact of Multi-Drug Resistant Pathogens

This white paper defined multi-drug resistance as related to different bacterial pathogens; discusses sources of multi-drug resistance and how resistance genes are transmitted among different strains and different species of bacteria; identifies multi-drug resistant bacteria associated with different foods and food production animals; evaluates efficacy of interventions to prevent development of multidrug resistance and to prevent contamination of foods with multidrug resistant pathogens; and recommends risk mitigation strategies in a preventive food safety process management system.

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Objectives

• Define multi-drug resistance as related to different bacterial pathogens
• Discuss sources of multi-drug resistance (human and animal) and how resistance genes are transmitted among different strains and different species of bacteria
• Identify multi-drug resistant bacteria associated with different foods and food production animals
• Evaluate efficacy of interventions to prevent development of multidrug resistance and to prevent contamination of foods with multidrug resistant pathogens
• Recommend risk mitigation strategies in a preventive food safety process management system

Conclusions

Scientific literature databases and relevant government publications from U.S. and other countries were searched for information on multidrug-resistant (MDR) pathogens and their public health impact. Search topics included mechanisms and evolution of antibiotic resistance, particularly MDR, transfer of resistance genes among bacteria, presence of MDR bacteria in animals (livestock, companion animals, and wild animals), the environment, and foods, and strategies to prevent development of multidrug resistance and to prevent contamination of foods with multidrug resistant pathogens. A summary of the white paper follows.  The complete report is available on the AMIF website (www.amif.org).

Multidrug resistance in microbes has become very widespread geographically with newly evolved MDR strains spreading around the world in a fairly short time. This is not just a problem of developed countries where large quantities of antibiotics are used for human medicine and in animal agriculture. Less developed countries often do not have adequate controls on use, sale and distribution of antibiotics so that drugs may be used to treat illnesses for which they are ineffective and persons using antibiotics may not realize the importance of completing a course of treatment. While there is some level of resistance to antimicrobials in environmental bacteria that have not been exposed to human and veterinary drugs, the widespread use of antibiotics in medicine and agriculture has driven the selection of microbes with greater levels of resistance thereby significantly increasing costs for treatment of some common infections as well as their morbidity and mortality.

Humans may be potentially exposed to MDR pathogens through a variety of routes including: environments at health care facilities, farm environments and animals, companion animals and their food, foods from animals carrying MDR bacteria, fresh produce carrying MDR pathogens acquired from contaminated soil or water, and exposure to other individuals carrying MDR microbes.

Several reviews have documented the increasing trends of resistance to multiple drugs in diseases such as tuberculosis, gonorrhea, and typhoid fever. Surveillance studies have also documented increasing trends in multidrug resistance in many other pathogens, although there are a few reports of the decline of certain multidrug pathogens. For example, MRSA is still a major health concern, but numbers have declined in some healthcare facilities that have adopted stringent controls on antibiotic usage and screening and treatment of incoming patients to prevent importation of new sources of MRSA into hospitals.

Deliverable

Strategies for controlling use of antimicrobials need to be implemented in both human and animal medicine and agriculture and in countries around the world. Resistant microbes can spread rapidly from where they originated to far distant places and countries.