- Prescribing Advice for GPs - https://www.prescriber.org.uk -

Antibiotic use increases resistance in individuals

A research article published this week in the British Medical Journal has demonstrated that the prescription of antibiotics to children in primary care leads to a short term increase in resistance in the individual that is sufficient to sustain a high level of antibiotic resistance in the population.

The study recruited 119 children who presented in primary care with an acute respiratory tract infection. 71 of the children were prescribed a beta-lactam antibiotic. Antibiotic resistance was assessed at recruitment and after 2 and 12 weeks using two methods; minimum inhibitory concentration of ampicillin and presence of resistance elements in Haemophilus isolates from throat swabs.

Prescription of amoxicillin more than tripled the minimum inhibitory concentration for ampicillin (9.2 µg/ml v 2.7 µg/ml, P=0.005) and doubled the chance of resistance elements being detected (67% v 36%; relative risk 1.9, 95% confidence interval 1.2 to 2.9) at 2 weeks. By 12 weeks resistance had fallen to baseline levels.

The authors conclude that "substantial and sustained changes in antibiotic prescribing in the community" are required to reverse the endemic presence of bacterial resistance in UK children. They also suggest that, if a second course of antibiotic treatment is considered necessary within 12 weeks, a beta-lactamase inhibitor - antibiotic combination (for example co-amoxiclav) may be an appropriate choice.

Action: Clinicians should continue implementing strategies to reduce overall prescribing of antibiotics to minimise the risk of antibiotic resistance. Where repeated courses are considered necessary, antibiotic resistance should be considered during antibiotic selection.