Children are at substantially increased risk of contracting drug-resistant infections in the months after taking a course of antibiotics, a leading public health official has warned.

Paul Cosford, medical director at Public Health England, told MPs on Wednesday that children are 12 times more likely to contract drug-resistant infections in the three months after being prescribed antibiotics, suggesting that their unnecessary use poses a direct risk to individual patients as well as a broader threat to society as a whole.

How big a problem is antibiotic resistance? Antibiotic resistance is an inevitable consequence of natural selections. When bacteria are exposed to antibiotics, occasionally some resistant strains will be left behind and multiply into hardier forms of the infection. The eventual result is "super bugs" like MRSA that are impossible to eradicate using frontline drugs. A report commissioned by the UK government estimated that there are 700,000 deaths globally each year linked to drug-resistant infections. Without the development of new, effective antibiotics, this figure could rise to 10 million deaths annually by 2050 and would make antimicrobial-resistant infections the biggest global killer.

“We’ve got good evidence that if you or I have a course of antibiotics now, within three months our risk is three times to get a resistant infection of some sort because we’ve had the antibiotics affecting all the organisms in our bodies,” he told the Science and Technology Select Committee. “If you’re a child you’re 12 times more likely to get a resistant infection in the three months after a course of antibiotics.”

He said the figures, based on two major reviews, highlighted the need to continue driving down our reliance on the drugs. “There is a growing body of evidence that taking antibiotics makes it more likely that your next infection will be a resistant one, so prudent use of these life-saving medicines is essential,” he told the Guardian.

The study cited by Cosford, in fact found that children who had urinary tract infections (cystitis) were 13.23 times as likely to have contracted drug-resistant strains if they had been given antibiotics in the previous six months.

In a previous survey, 90% of GPs said they come under pressure from patients to hand out the antibacterial medication, and 45% said they had done so knowing it would not help.

Mark Woolhouse, professor of infectious disease at the University of Edinburgh, said that the figures matched his qualitative experience from the clinic. “In hospitals you definitely do get patients who will get a string of different drug-resistant infections,” he said.

Antibiotics pose a risk of subsequent illness, he said, because the drugs do not uniquely target the infection, but also eradicate useful bacteria in the gut. “They change the ecology of the gut, a bit like using a pesticide in a rich woodland,” he said. In the ecological niche that opens up after a course of antibiotics, opportunistic infections can spring up.

“This comes with the proviso that people should follow their doctor’s advice,” he added. “Antibiotics are a good thing when prescribed correctly, but they can have longer-term disadvantages of all kinds.”

The committee heard that that overall Britain had made progress on reducing the use of antibiotics since the government asked the economist Jim O’Neill to produce a report on antimicrobial resistance two years ago.

Prescriptions of antibiotics fell by 7.3% in the financial year 2015-16 compared with the previous year, Cosford told the committee.

Farms are also on track to meet a Defra target for 2018 of reducing average antibiotic use on farms to 50mg of drug per 1kg of meat produced (56mg this year, compared to 62mg in 2014). The target is designed to combat the blanket use of antibiotics as a way of boosting the growth of livestock – particularly poultry and pigs.

Certain strains of drug resistant infections are decreasing, the committee heard, with only 800 cases of MRSA bloodstream infections last year, compared to 7,000 in 2003. “When we focus on specific infections that are causing a problem then we can be extremely successful,” said Cosford. However, a more worrying trend was the rise in drug resistant E coli strains, he said, mostly linked to urinary tract infections.

O’Neill said that the current government appeared “less passionate” about the issue than the previous administration. “There is interest, perhaps not with the same passion as with David Cameron,” he said. “The prime minister himself and the chancellor played an active role in international engagement on the issue. I have not seen this government talk about it anything like as much as the previous leadership did.”

He added that it was crucial for policy-makers to make international efforts now rather than waiting for the “scary outbreak of a crisis”.

“We need to stop treating these things like sweets,” O’Neill said. “We all need to be re-educated that these things aren’t a magical solution for as many things as people think.”



