Meetings

Standing Advisory Committee on Antimicrobial Resistance

A recent meeting heard about the problem of antimicrobial resistance and reflected on what hospital pharmacists can do to address the issues with the help of new Government funding. Gareth Jones, editor, Hospital Pharmacist, reports

The “Resistance is useless” conference, organised by the Standing Advisory Committee on Antimicrobial Resistance, in conjunction with the National Prescribing Centre and the Royal Pharmaceutical Society, took place in London on 7 July

Antimicrobial drug resistance is an increasing, inevitable global problem

Antimicrobial drug resistance is an increasing and accumulating but inevitable global problem. However, the UK is facing a more immediate problem, with methicillin-resistant Staphylococcus aureus (MRSA) being more prevalent than in any other European country. “This conference is the launch of an important initiative involving hospital pharmacists in tackling antimicrobial resistance,” said Richard Wise, consultant medical microbiologist, City Hospital, Birmingham, and chairman, Standing Advisory Committee on Antimicrobial Resistance (SACAR). “Today is the first day on a national level to get things rolling with antibiotic pharmacists. I know certain hospitals have been doing something for a considerable period of time and we can build upon their experiences. Clinical pharmacists should be a conduit for communication. This can help deal with poor compliance with guidelines and the low knowledge base of many clinicians,” he said.

Commenting on the problem of antibiotic over-use in hospitals, Professor Wise criticised medical staff for unnecessarily prescribing antibiotics such as cefuroxime for many of their patients. It should be possible to achieve a reduction in antibiotic use across primary and secondary care of 50 to 60 per cent, although it will be difficult, he suggested. Turning to the use of antimicrobials in the community, Professor Wise said that there had been a 24 per cent reduction in use between 1995 and 2000. “It is not clear why antimicrobial use has declined, but with a six-fold difference between certain practices, it is clear that more can be achieved,” he said.

Allowing nurses to prescribe antibiotics may lead to an increase in antimicrobial resistance, according to Professor Wise. “If more people can prescribe, the danger is that more will be prescribed,” he said. “We in the UK are moving in one direction, expanding our prescribing base, and across Europe many countries are moving in the opposite direction with more restrictive prescribing of antimicrobials.” The nurse formulary is being extended to include products for the treatment of human and animal bites, acne, impetigo and urinary tract infections. In addition, walk-in centres will have patient group directions (PGD) for infective conjunctivitis, widespread impetigo and severe tonsilitis. No microbiological investigations are required in the PGDs, which was a concern to Professor Wise.

Pharmacists should be aware that if one of a group of antimicrobials is to be used, consideration should be given to using the one with the most reasonable pharmacokinetic/ pharmacodynamic parameters, according to Professor Wise. In a Canadian study, a relationship was found between macrolide-resistant Streptococcus pneumoniae and azithromycin use. Azithromycin differs from erythromycin (another macrolide) in that it is longer acting, while achieving lower serum levels. Areas of high azithromycin use, as a percentage of total macrolide use, had a high incidence of macrolide resistance, and vice versa. “Azithromycin is causing problems,” he added.

“ Surveillance should be about information for action, not an end in itself,” said Professor Wise. Surveillance is done badly across most of the world, he added. Good surveillance underpins two of the key tools for managing the problem of resistance: reducing selection pressure (prescribing) and controlling cross-infection. SACAR has a number of priorities in relation to surveillance, and developing a national hospital prescribing database, linked to laboratory and clinical data, is one area in which pharmacists’ contributions will be invaluable. Improving standardisation of laboratory methods for defining resistance is also a priority.

One of the big unknowns is whether reducing antimicrobial use will lead to a decrease in microbial resistance, said Professor Wise. “Will we see a rapid decline or no change? We do not know the answer to this, and we have to find out”, he said. “The outcome is likely to depend on the drug, the bug and the clinical setting, and will probably vary considerably.”

Can resistance trends be reversed?

It is not clear if the trend of increasing antibiotic resistance rates can be reversed, according to Erwin Brown, consultant medical microbiologist, Frenchay Hospital, Bristol. Most of the studies that have evaluated the efficacy of interventions to reduce inappropriate antibiotic prescribing have not used resistance rates as an outcome measure. They have used easier targets, such as cost, appropriateness of prescribing and prescribing levels. When resistance rates have been used as an outcome measure, it is difficult to determine the relative contribution of the intervention and other factors such as infection control measures. For example, a recent study from the US showed a 27 per cent decrease in overall antibiotic use following the introduction of an antibiotic management programme. More than $2m (£1.1m) was saved in the first three years of the programme, but no change in the susceptibilities of the common aerobic gram-negative bacilli were demonstrated. “Even if we were to eliminate inappropriate antibiotic prescribing, appropriate antibiotic prescribing can also drive up resistance rates,” said Dr Brown.

There are a number of factors which contribute to the increasing rate of resistance: increasing numbers of patients, older and sicker patient populations, larger numbers of immunocompromised patients and novel procedures such as the implantation of prosthetic devices, which leads to new types of infections. Greater use of antibiotics and the tendency to use new drugs when they become available in preference to older drugs that would do the job just as well are also factors, according to Dr Brown. Consequences for patients of developing infections caused by multidrug resistant bacteria include increased morbidity, increased mortality, prolonged hospital stay and a negative impact on waiting lists.

Between 25 and 50 per cent of antibiotic prescribing in hospital is inappropriate. In the past, the pharmaceutical industry has provided new drugs to deal with the problem of resistance caused by this inappropriate use, according to Dr Brown. However, of the 506 drugs currently being researched by the pharmaceutical industry, only six are antibacterials, and none of these has a novel mechanism of action.

In the UK hospital sector there are no national antibiotic prescribing data. In the absence of these data surrogate markers must be used to monitor antibiotic use, said Dr Brown. A recent survey of 253 UK hospitals found that 76 per cent had a formulary, 56 per cent had a policy/strategy and 87 had guidelines for antibiotic prescribing. These figures had changed little from a similar survey conducted 10 years earlier. According to Dr Brown, the obstacles to improving antibiotic prescribing include the failure of health care professionals to take ownership of the problem (they believe that infection control and microbiologists should deal with it), the total disregard for cost effectiveness, the lack of standard data and chronic under-resourcing.