Meetings

Combating resistance to antibiotics

A joint meeting of the Royal Pharmaceutical Society's Hospital Pharmacists Group and Industrial Pharmacists Group, held on 28 November, focused on the problem of resistance to antimicrobials. Olumide Cole reports

Some of the speakers at the conference, from left, Mike Vickers, Southampton University Hospitals NHS Trust, Alisdair MacGowan, Southmead Hospital, Bristol, Alison Ewing, Royal Liverpool and Broadgreen University Hospitals NHS Trust, David Livermore, Public Health Laboratory Service, Jane Sharp, Northwick Park Hospital, Middlesex and Jonathan Underhill, National Prescribing Centre

Controlling the use of antibiotics involves surveillance, development of guidelines, education of prescribers, pharmacist interventions in prescribing and removing or restricting the use of drugs. However, according to Mike Vickers, microbiology liaison pharmacist at Southampton University Hospitals NHS Trust, "any policy that attempts to control antibiotic use can only be successful if there is active follow-up to ensure that it is maintained in the long-term".

At the Southampton trust, due to implementing guidelines which include the avoidance of routine use of cephalosporins in lower respiratory tract and urinary tract infections, the number of cases of Clostridium difficile infection was reduced from 235 in 1999/2000 to 206 in 2000/01. At an estimated cost of £4,000 per case, this represented a total saving of £116,000.

Another initiative that has proved successful at the Southampton hospital is the introduction of specialist ward rounds involving clinical pharmacists and clinical microbiologists, where patients needing interventions are identified. Pharmacists are keen on the initiative and the rounds sometimes lead to changes in patients' therapy by consultants.

In response, Dr Alisdair MacGowan, chairman of the conference and consultant microbiologist at Southmead Hospital, Bristol, commented that one drawback of the initiative, in the long term,is that it could lead to a "de-skilling" of the clinicians as they will become dependent on the specialist rounds.

Surveillance

Are GPs to blame for abuse of antibiotics?

A discussion session at the conference centred on the fact that most inappropriate prescribing of antibiotics occurs in the community. GPs are often put under pressure by patients demanding antibiotics for ailments such as colds or sore throats, when over-the-counter (OTC) remedies would have sufficed.

There was general agreement with the sentiments expressed by one commenter, who said that "support and advice for antibiotic prescribing in the community should be increased". Some of the participants believed that the problem was one of a lack of assertiveness on the part of GPs. One participant stated: "GPs have to learn to say no to patients".

But there are other problems. For example, it will be hard to convince patients who obtain free prescription drugs to pay for OTC remedies at a pharmacy.

One participant suggested that "perhaps more educational activity should be targeted at patients". This seemed sensible enough until another commenter announced: "Research has shown that most patients do not go to their GPs expecting antibiotics." Rather, GPs are prescribing antibiotics because they believe that patients want antibiotics to be prescribed for them!

Surveillance is required to monitor the prevalence of established resistance to antibiotics, detect the emergence of new resistance problems and test the effects of interventions. In an ideal world, to make the surveillance complete, all patients with an infection would have a specimen taken from them. This specimen would then be cultured and subjected to a wide range of antibiotics.

In the real world, however, most patients do not have a specimen taken from them, lamented Dr David Livermore, director of the Public Health Laboratory Service's antibiotic resistance monitoring and reference laboratory. Even where specimens are taken, they are subjected to only a few antibiotics.

Routine data is obtained when hospitals send results of antibiotic sensitivities to the PHLS. There is an abundance of this data, which means that further testing of isolates is not needed. Routine data can provide information that is quite useful. For example, it was found from such data that, up till 1993, methicillin-resistant Staphylococcus aureus (MRSA) was only a small proportion (less than 5 per cent) of S. aureus reports, whereas now, over 45 per cent of such reports are of the MRSA genre.

However, Dr Livermore stressed that there are limitations to the use of routine data. Many isolates are incompletely identified and some laboratories test certain antibiotics against selected subsets of isolates whereas others test them against all. Speciation [species identification] of isolates is often not complete. For example, Escherichia coli, Enterobacter and Klebsiella are all classified as coliform. The reasons for testing also differ. Dr Livermore said routine data is usually more reliable at detecting sensitivity than specificity.

In order to overcome the limitations of routine data, sentinel surveys are carried out. In this case, centralised testing is performed on isolates collected from the different centres. Sentinel surveys can be sponsored by the pharmaceutical industry or the public sector. Testing in such surveys is standardised and performed to high standards. Where sentinel surveys have been carried out repeatedly, they can be compared to see if there has been a change in the resistance pattern. Despite the advantages of sentinel surveys however, throughput is small and there is sample bias. The problem of bias is particularly evident in the community where, for example, only 3 per cent of patients with respiratory tract infections (RTIs) have specimens sent to the laboratory, in spite of the fact that RTIs constitute 50 per cent of antibiotic usage in the community. Also, older age groups are three times more likely to be sampled. Such low rates of sampling could lead to an overestimation of the resistance problem for certain antibiotics, for example, trimethoprim.

Dr Livermore said that the strategy of the PHLS is to "cross-validate the resistance rates from routine and sentinel surveys, and to investigate when these appear to differ".

Licensing of antibiotics

Dr Mair Powell, clinical assessor, licensing division of the Medicines Control Agency, said that the use of anti-infective drugs has implications for public health, therefore special considerations apply when they are being assessed as suitable for marketing in the European Union. These considerations include the need to include a discussion of resistance and cross-resistance, and if applicable, to give an EU range of percentage acquired resistance.

In the summaries of product characteristics, the pharmacodynamics section (section 5.1) of anti-infectives now contains a statement that "the prevalence of resistance may vary geographically and with time for selected species, and local information on resistance is desirable, particularly when treating severe infections".

Dr Powell said that licensing authorities are well aware of the problem of antimicrobial resistance and the need for new drugs, but that action is only possible when there is robust evidence to support any measures proposed.

Community pharmacy

Infection management group

A new group for members of the United Kingdom Clinical Pharmacy Association with an interest in infection management is being formed. The UKCPA Infection Management Group aims to facilitate networking, organise educational events and share best practice. Further information on the group is available from Bryony Dean (bdean@hhnt.org) or Wendy Lawson (wlawson@hhnt.org). Those wishing to join the group can contact Pat Kennedy (Pkennedy@ukcpa.u-net.com).

Community pharmacists have virtually no control over the use of antibiotics, despite the fact that 80 per cent of antibiotic prescribing takes place in the community. In hospitals, clinical information is usually available and pharmacists may even be present to intervene when antibiotics are being prescribed. On the other hand, community pharmacists are simply presented with a prescription for antibiotics with no indication as to what they are being used for.

Alison Ewing, director of pharmacy at the Royal Liverpool and Broadgreen University Hospitals NHS Trust described this situation as unfortunate. "We are not allowed to use our professional judgement", she said. Miss Ewing suggested that community pharmacists should be involved when formularies are being drawn up. They will then be able to challenge prescriptions for antibiotics not included in the formulary. In addition, community pharmacists also have the opportunity to educate patients on antibiotics.

Asked what "carrot or stick" could be dangled before GPs to ensure proper prescribing of antibiotics, Miss Ewing said that the GPs should be made to know that clinical governance requires that antibiotics are not used inappropriately.

Role of NPC

Antibiotics have changed the lives of people more than any other pharmaceutical product, said Jonathan Underhill, manager, "training the trainers", National Prescribing Centre. However, resistance is an increasing problem and if care is not taken, routine infections may become life-threatening.

Health professionals should be "sensible about using antibiotics", according to Mr Underhill. Some of the strategies that the NPC is adopting in primary care include the use of local guidelines, a "no repeats for antibiotics" policy, raising local awareness, and delayed prescribing (providing patients with prescriptions but asking them to present it at a future date if the infection has not cleared).

Olumide Cole is on the staff of the Hospital Pharmacist