The global burden of antimicrobial resistance

Antimicrobial Resistance (AMR) poses a global challenge. No single country, however effective it is at containing resistance within its boundaries, can protect itself from the importation of multi-drug resistan organisms (MDRO) through travel and trade.

The global nature of AMR calls for a global response, both in the geographic sense and across the whole range of sectors involved. Nobody is exempt from the problem.

Despite an increasing prevalence of MDRO worldwide, the health and economic impact of these organisms is often underestimated.

The impact of AMR worldwide is significant, both in economic terms, and clinical morbidity and mortality because it may:

  • lead to some infections becoming untreatable;
  • lead to inappropriate empirical treatment in critically ill patients where an appropriate and prompt treatment is mandatory;
  • increase length of hospital stay, morbidity, mortality and cost; and
  • make necessary alternative antimicrobials which are more toxic, less effective, or more expensive.

Antimicrobial resistance is a natural phenomenon that occurs as microbes evolve. However, human activities have accelerated the pace at which microorganisms develop and disseminate resistance. Incorrect and inappropriate use of antibiotics and other antimicrobials, as well as poor prevention and control of infections, are contributing to the development of such resistance.

The impact of AMR worldwide is significant, both in economic terms, and clinical morbidity and mortality.

Although the optimally effective and cost-effective strategy to reduce AMR is not known, a multifaceted approach is most likely to be successful.

Many calls to action on antimicrobial resistance have been made over the past years. Countries with the strictest policies on antibiotic prescription now report the lowest rates of bacterial resistance. However in most high income countries, clinical use of antibiotics has not declined, despite frequent calls to curtail overuse.

The World Health Organization (WHO) is now leading a global effort to address antimicrobial resistance. At the 68th World Health Assembly in May 2015, the World Health Assembly endorsed a global action plan to tackle antimicrobial resistance. It sets out five strategic objectives:

  • to improve awareness and understanding of antimicrobial resistance;
  • to strengthen knowledge through surveillance and research;
  • to reduce the incidence of infection;
  • to optimize the use of antimicrobial agents; and
  • to develop the economic case for sustainable investment that takes account of the needs of all countries, and increase investment in new medicines, diagnostic tools, vaccines and other interventions.

AMR has emerged as one of the principal public health problems of the 21st century. This has resulted in a public health crisis of international concern, which threatens the practice of modern medicine, animal health and food security. The substantial problem of AMR is especially relevant to antibiotic resistance (ABR), although antifungal resistance is increasing at an alarming rate. Although the phenomenon of ABR can be attributed to many factors, there is a well-established relationship between antibiotic prescribing practices and the emergence of resistant bacteria.

Combating resistance has become a top priority for global policy makers and public health authorities. New mechanisms of resistance continue to emerge and spread globally, threatening our ability to treat common infections. Antibacterial and antifungal use in animal and agricultural industries aggravates selective pressure on microbes. A One Health approach is urgently required.

An alarming pattern of resistance involving multi and pandrug-resistant Gram-negative bacteria is currently emerging; multi-resistant Enterobacteriaceae is an increasing major concern worldwide. Comparative antimicrobial resistance data worldwide are difficult to obtain and inevitably suffer from bias. In high income countries, MDRO have historically been confined to the hospital setting. Since the middle of the 2000s, however, MDRO such as the extended-spectrum producing beta-lactamase Enterobacteriaceae (ESBLs) have been widespread in the community setting .

Throughout the 1980s and 1990s, prolonged hospital and intensive care unit stays were considered among the most important risk factors for harboring ESBL Enterobacteriaceae along with exposure to broad-spectrum antibiotics. However, most ESBL producing infections are now also in the community and healthcare-associated settings as demonstrated in studies from Europe and the Southeastern USA.

The burden of MDRO infections in low-middle income countries (LMIC) is difficult to quantify, because surveillance activities to guide interventions require resources. In these countries, routine microbiologic culture and sensitivity testing, especially in rural hospitals, are not performed, due to lack of personnel, equipment and financial resources. As a result antimicrobial therapy is empirical and a small collection of antimicrobials may be overused. This approach, although relatively inexpensive, may further increase the emergence of AMR and hence sub-optimal clinical outcomes. Therefore, although resistance containment interventions in healthcare structures have mostly been implemented in high-income countries, there is a pressing need to intervene in the resistance pandemic also in LMIC.

An effective and cost-effective strategy to reduce AMR should involve a multi-faceted approach aimed at optimizing antibiotic use, strengthening surveillance and IPC, and improving patient and clinician education regarding the appropriate use of antibiotics. Although the current magnitude of the problem and its extent in both the community and the hospital adds to the complexity of any intervention, these are still necessary as healthcare workers play a central role in preventing the emergence and spread of resistance.

 

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