27 july 2007

Antibiotics given to children continue to raise resistance levels in population

Antibiotics such as amoxicillin given to children have no long-term effect to the child but contribute to a high level of antibiotic resistance in the population, Oxford researchers have found.

Despite a fall in consumption of penicillin over the last ten years, it has recently been observed that community antibiotic prescribing is again on the rise. Researchers at the Department of Primary Health Care set out to assess its effect on antibiotic resistance in individual children.

In a paper published by the British Medical Journal on 28 July 2007, the group reports the results of a study with 119 Oxfordshire children with acute respiratory tract infection.

71 of that cohort were given the moderate-spectrum penicillin amoxicillin, while 48 received no antibiotic. Throat swabs were taken at the start of the study and again at two and 12 weeks to measure whether resistant bacteria were present.

In children who did not receive an antibiotic, there was no increase in the proportion carrying resistant bacteria in the throat from the initial level at 2 or 12 weeks.

However, in children who received an antibiotic, the number carrying resistant bacteria more than doubled at the two-week follow-up, but fell back close to the initial level by 12 weeks.

These results show that prescribing amoxicillin to a child in general practice doubles the risk of recovering a penicillin resistance element from that child’s throat two weeks later. Although this effect is temporary in the individual child, it may be sufficient to sustain a high level of antibiotic resistance in the population.

Dr Mant, who co-authored the paper, said: ‘Cutting resistance rates will require substantial and sustained changes in antibiotic prescribing in the community. Doctors could, for example, prescribe shorter courses of treatment, or only prescribe antibiotics in well defined and exceptional circumstances.’

The paper ‘Effect of antibiotic prescribing on antibiotic resistance in individual children in primary care: prospective cohort study’ is available online.