A 20-year study has shown that 1 in 10 of all antibiotic prescriptions fail to treat the infection for which they were prescribed. This is set against a backdrop of the World Health Organisation declaring that the issue of antibiotic resistance is a global public health crisis.
The study was carried out by researchers at Cardiff University. They state that although many previous studies have assessed antibiotic resistance in hospitals, little is known about the frequency and pattern of antibiotic resistance in primary care.
The new study gathered data on antibiotic treatment failure rates in UK primary care. The researchers say that the UK is one of the few countries where it is possible to access appropriate data for assessing failure of antibiotic prescriptions, because of the way data is recorded in its National Health Service.
Data was drawn from the Clinical Practice Research Datalink, which stores the records of more than 14 million individuals, obtained from 700 primary care practices across the UK.
The Cardiff team analysed data from 1991-2012 and focused on the four most common kinds of infection:
- Upper respiratory tract infections
- Lower respiratory tract infections
- Skin and soft tissue infections
- Acute otitis media
The results show that overall antibiotic failures rose from 13.9% in 1991 to 15.4% in 2012. Antibiotics prescribed to treat bronchitis and pneumonia and other lower respiratory tract infections were found to be the least successful, showing an increased failure rate of 35%.
Throughout the study period, the treatment failure rates for the commonly prescribed antibiotics amoxicillin, penicillin and flucloxacillin remained below 20%.
In addition, the failure rate of antibiotics that are not normally prescribed as first-line treatments also showed a marked increase. One example of this rise can be observed in the failure rates of trimethoprim, normally used to treat upper respiratory tract infections, which had risen 40% across the treatment period.
The author of the study, Professor Craig Currie says there is a strong link between the rise in antibiotic treatment failure and an increase in prescriptions. From 2002-2012, the proportion of infections being treated with antibiotics rose from 60% to 65%. This period of 2002-2012 was also when the biggest increase in antibiotic failure rates occurred.
"These episodes of failure were most striking when the antibiotic selected was not considered first choice for the condition treated," Professor Currie says. He adds:
"Given the lack of new antibiotics being developed, the growing ineffectiveness of antibiotics delivered through primary care is very worrying indeed. There is a mistaken perception that antibiotic resistance is only a danger to hospitalised patients, but recent antibiotic use in primary care is the single most important risk factor for an infection with a resistant organism. Furthermore, what happens in primary care impacts on hospital care and vice versa."
The study is published in the BMJ.