Efforts to Circumvent Drug Resistance by Bacteria and Fungi Doomed to Failure

[Guest guest]

[somewhat depressing news, if true.]

Permanent resistance to antibiotics cannot be prevented

10 December 2004

Dutch research has shown that the development of permanent resistance

by bacteria and fungi against antibiotics cannot be prevented in the

longer-term. The only solution is to reduce the dependence on

antibiotics by using these less.

The reduced effectiveness of antibiotics is not only an important

issue for human health. For example, plants can have a gene inserted

which enables them to secrete an antibiotic against fungi. Siemen

Schoustra believes that the added value of these genetically-modified

crops is smaller than thought, as the fungus soon becomes permanently

resistant to the antibiotic so that the plants still become diseased.

The first resistant plant fungi have already been found in India.

Evolution is the cause of the resistance. However this resistance

should disappear again, as resistant fungi and bacteria grow less

well in an environment without the substance they are resistant to

and are therefore outstripped by their faster-growing non-resistant

counterparts. Yet, some variants remain permanently resistant.

Permanent resistance occurs in two stages. The fungus first of all

becomes resistant due to a change in its DNA and then a second such

change ensures that the resistant type eventually grows just as

quickly as the non-resistant types. The result is a sort of super

fungus, which is resistant and can also grow quickly under all

circumstances. This leads to the resistance becoming permanent and

therefore the effectiveness of antibiotics being reduced.

Researchers are trying to hinder the development of resistance in

bacteria and fungi in an attempt to prevent the antibiotics from

becoming obsolete. Their efforts are primarily focussed on

understanding and preventing the first stage, whereas the second

stage is often omitted. Schoustra's research reveals that hindering

the second stage (compensating for the negative effects of

resistance) is extremely difficult, as bacteria and fungi can

compensate for the negative effects of resistance in so many

different ways. Therefore, the only solution is to reduce the

dependence on and the use of antibiotics.

The research was funded by the Netherlands Organisation for

Scientific Research.