Antimircrobial Resistance: Future Perspectives

There are no immediate solutions to the myriad problems related to AMR. The forces driving the emergence and spread of resistance, as well as the interventions needed for containment, are deeply integrated into the organization of health-care systems and society as a whole.

Any successful approach to AMR containment will have to include efforts to curtail the inappropriate prescription of antibiotics to both animals and humans, and at the same time reduce the need for antimicrobial treatment by effective infection control measures.

The so-called ‘low-prevalence countries’ in Northern Europe demonstrate how cultural and societal determinants can act to preserve antimicrobial susceptibility, but it is not easy to see how this can be effectively disseminated to other countries. One may even question whether experiences from the Nordic countries and the Netherlands will have any relevance to countries where AMR is already established at a high level.

In spite of the continuing focus on prudent drug use, physicians and veterinarians will often maintain their established prescription practices, fearing under-treatment or loss of patient consumer confidence. Furthermore, most countries do not have effective enforcement of drug legislation, with the consequent widespread over-the-counter sales of antibiotics, although this is often formally illegal. Internet pharmacies represent another challenge in this respect.

Implementation of infection control programs in order to reduce the burden of disease is not feasible in many settings due to lack of adequate funding or breakdown of society’s structure due to poverty, failed states, natural disasters and war.

However, there are areas which offer some hope for changes in the right direction. The emergence and spread of macrolide-resistant group A streptococci in Finland, as reported by Sappala et al. (1997), and penicillin-resistant pneumococci in Iceland in the late 1980s, as shown by Arason et al. (2006), were halted and eventually reversed through concerted efforts including improved prescription practices and infection control measures.

It has been argued that this reversal of resistance should be explained at least partly by escalating herd immunity against specific resistant bacterial clones, but the overall conclusion is nevertheless that AMR is not necessarily an irreversible phenomenon. A similar downward trend in penicillin- resistant pneumococci has recently been noted in Spain.

France has managed to reduce the consumption of antibiotics substantially through massive information campaigns directed toward both prescribers and the general public over the last few years, but it is too early to determine the effect this will have on resistance rates.

Furthermore, the use of antimicrobials as growth promoters in animal husbandry has largely been abandoned in Europe. The anticipated increase in therapeutic veterinary usage has so far been very limited. It is also encouraging that the introduction of bacterial vaccines against H. influenzae, and just recently also shown for S. pneumoniae by Kyaw et al. (2006), has led to substantially reduced prescription of antibiotics to children and also lower prevalence of resistance.

The underlying mechanisms for this decrease are probably complex. Vaccine-induced immunity toward resistant serotypes can directly reduce the transmission of these clones, and the lower overall prevalence of infection may at the same time lead to reduced selection by antibiotic exposure. One can therefore hope for a downward spiral in antimicrobial usage and resistance as opposed to the escalating trend over the previous decades.

Candidate vaccines for bacterial pathogens, such as staphylococci, as well as rotavirus and other agents often treated by antibiotics, will undoubtedly have a large effect in the area of drug resistance. It will of course be of critical importance to ensure sufficient funding to extend these benefits also to the population of the developing world.

Finally, in the area of infectious disease, there may be signs of renewed interest from pharmaceutical and diagnostic companies in development of novel medicines and diagnostic tools supporting the shift from empiric to pathogen-directed therapy. It is hoped that we can learn from past experiences of substandard diagnostics and uncritical antimicrobial usage so that infectious diseases will remain manageable in the future. As we should have learned by now, mankind should handle microorganisms with great care, as they are the true rulers of this world.