Resistant Bacteria a Fact of Life

Report says no amount of resources will end the problem, which is not caused by 'overuse' of antibiotics.

Published on: Apr 1, 2010

Antibiotic resistance will never go away.

Resistance will prevail no matter how many drugs, money or resources are thrown at it, according to a recent report by the American Academy of Microbiology.

Instead of trying to eliminate antibiotic resistance, the academy concludes in its report that public health officials, clinicians and scientists must find effective ways to "cope" with antibiotic-resistant bacteria that are harmful to people and animals and to "control" the development of new types of resistance.

The view that antibiotic resistance is simply an undesirable consequence of antibiotic abuse or misuse is "inaccurate," the academy said. In reality, the report states, the rate of antibiotic resistance emergence is related to all uses of these drugs, not just misuse. Likewise, the total amount of antibiotics used and the environment also play roles.

More sanitation needed

The report indicated a key factor behind resistance in human and animal health environments may actually be a lack of adequate hygiene and sanitation, which enables rapid proliferation and spread of pathogens.

"Each antibiotic is injurious only to a certain segment of the microbial world, so for a given antibacterial, there are some species of bacteria that are susceptible and others that are not. Bacterial species insusceptible to a particular drug are 'naturally resistant,'" the academy said.

Those species that were once sensitive to an antibiotic but eventually became resistant to it have an "acquired resistance."

Defining resistance

Antibiotic resistance is the acquired ability of a pathogen to withstand an antibiotic that kills off its sensitive counterparts. It originally arose from random mutations in existing genes or from intact genes that already serve a similar purpose.

Exposure to antibiotics and other antimicrobial products -- whether in the human body, in animals or in the environment -- applies selective pressure that encourages resistance to emerge that favors both naturally resistant and acquired resistance strains.

Horizontal gene transfer, in which genetic information is passed between microbes, allows resistance determinants to spread within harmless environmental or commensal microorganisms and pathogens, thus creating a reservoir of resistance.

Resistance is also spread by the replication of microbes that carry resistance genes, a process that produces genetically identical (or clonal) progeny.

Changing course

The academy report said rapid diagnostic methods and surveillance are some of the most valuable tools in preventing the spread of resistance. As such, access to more rapid diagnostic tests that could determine the causative agent and antibiotic susceptibility of infections would provide for better decision-making with respect to antibiotic use, help slow the selection of resistant strains in clinical settings and enable better disease surveillance.

A rigorous surveillance network to track the evolution and spread of resistance is also needed and would probably result in significant savings in health care, the academy said.

"Controlling antibiotic-resistant bacteria and subsequent infections more efficiently necessitates the prudent and responsible use of antibiotics. It is mandatory to prevent the needless use of antibiotics (e.g., viral infections, unnecessarily prolonged treatment) and to improve the rapid prescription of appropriate antibiotics to a patient," the academy said.

It also said delayed or inadequate prescriptions reduce the efficacy of treatment and favor the spread of the infection.

Animal agriculture

Regarding antibiotic use in animals, the academy said prudent use also applies.

"There are proven techniques for limiting the spread of resistance, including hand hygiene, but more rapid screening techniques are needed in order to effectively track and prevent spread in clinical settings. The spread of antibiotic resistance on farms and in veterinary hospitals may also be significant and should not be neglected. Research is needed to pursue alternative approaches, including vaccines, antisense therapy, public health initiatives and others," it said.

The report said for most drugs, increasing doses and shortening the treatment period apparently is less effective in selecting for resistance than the usual dose and regimen.

It added that every country should revise animal production practices with responsible use of antibiotics. The amounts used currently must be decreased or eliminated, it said.

Then the academy added: “There is no question but that research on the impacts of antibiotic use in agriculture on resistance in the clinic is scant and deserves more attention.”

Poor communication?

The academy also expressed concern over whether important messages about antibiotic resistance are getting across from scientists and infectious disease specialists to prescribers, stakeholders -- including the public -- health care providers and public officials.

"Innovative and effective communication initiatives are needed, as are carefully tailored messages for each of the stakeholder groups," the academy said.

The American Academy of Microbiology is the honorific leadership group within the American Society for Microbiology (ASM), the world's oldest and largest life science organization. The academy serves as a resource to governmental agencies, industry, ASM and the larger scientific and lay communities by convening colloquia to address critical issues in microbiology.

The academy convened a colloquium in October 2008 to discuss antibiotic resistance and the factors that influence the development and spread of resistance.

Participants whose areas of expertise included medicine, microbiology and public health made specific recommendations for needed research, policy development, a surveillance network and treatment guidelines. Antibiotic resistance issues specific to the developing world were discussed, and recommendations for improvements were made.

To read the full report, go to: Report.

Muirhead is editor of Feedstuffs magazine

Beef Producer Editor Alan Newport contributed to this article.