Do antibiotics help or harm?


Sylvia Thompson examines the role of antibiotics in treating common infections

Which common illnesses require antibiotics and which do not has become a big issue for GPs and the public at large.

While we all have a fuzzy understanding that the overuse of antibiotics increases the amount of resistant bacteria in our midst, many of us will still seek out a prescription for antibiotics when we find ourselves with a sore throat or respiratory infection.

And while the rise of MRSA is primarily associated with the overuse of antibiotics in hospitals, there are concerns that overuse of antibiotics in the community is leading to new forms of antibiotic-resistant bugs, which is resulting in more serious illnesses such as certain forms of pneumonia.

"There is an awareness of antibiotic-resistant infections but there is an ongoing need for more education of GPs and the public," says Prof Colin Bradley, professor of general practice at University College Cork who chairs a group responsible for antibiotic stewardship in the community.

It's a complex issue because on one level, new research is revealing that, for example, most ear infections in children will clear up with or without an antibiotic, yet some throat infections (which when tested were found not to be caused by the common streptococci bacteria) will still improve with an antibiotic because the medicine kills other bacteria.

Bradley says: "GPs are in some difficulty because of the uncertainty of the presenting illness.

If it is caused by a virus - which the majority of sore throats are - an antibiotic won't have any effect and even most of those with sore throats caused by streptococci bacteria, will recover without antibiotics yet there is a small percentage of patients at risk of further infection who need an antibiotic.

"The problem is that tests take some time to come back to the GP and some GPs will take a cautious approach, prescribing an antibiotic to almost everyone with a sore throat because it might benefit," he says.

"Others who don't prescribe risk having patients come back with more severe symptoms a few days later - or going to another GP who will prescribe an antibiotic immediately," he says.

A recent survey of GPs in the south of Ireland found that a high percentage of doctors overestimate the risk of missing something serious and therefore over-prescribe antibiotics.

Meanwhile, in Britain, a large study to determine which patients with sore throats will genuinely benefit from antibiotics is about to begin.

Dr Edmond Smyth, consultant microbiologist at Beaumont Hospital, says the hospital's courier service to GPs in the north Dublin area has allowed for a quicker turn-around for tests and therefore gives doctors more information before prescribing antibiotics to treat common infections.

"The problem is that our healthcare system militates against patients returning to their GPs for test results - both for financial reasons and because GPs are so busy - therefore there is an expectation of a fix-all on one appointment," says Smyth.

The now common practice among GPs to write deferred prescriptions - which are to be used only if the symptoms get worse - has helped somewhat.

However, some people's strong belief in the power of antibiotics to clear up infections means that they will immediately get their prescription medicine even though they have been asked to wait to see whether their symptoms get worse.

Bradley says: "There is a kind of folk belief that if you've phlegm in your throat, an antibiotic will break it up but the reality is that most common infections are benign and self-limiting even if some will take longer to clear up without an antibiotic."

Another contributing factor to the rise of antibiotic-resistant bugs is the practice among some doctors of using antibiotics which target a wider group of bacteria (known as broad-spectrum antibiotics) rather than antibiotics (known as narrow-spectrum antibiotics) which target only certain bacteria.

A recent study by the European Surveillance of Antibiotic Consumption found that narrow-spectrum antibiotics were used in only 10 per cent of cases in Ireland compared with 80 per cent of cases in Scandinavian countries.

"The potential problem with using broad spectrum antibiotics is that more bugs are exposed to antibiotics, some of which will acquire resistance to the antibiotic as resistance is developed through low-level exposure to antibiotics over time.

"Another difficulty is that broad spectrum antibiotics disturb the gastrointestinal flora [ie the good bacteria] so the patient with a respiratory illness may end up with another problem such as thrush because the candida fungi has taken hold due to the change of balance," says Bradley.

Dr Edmond Smyth believes better resourced hospital laboratories with more microbiologists and clinical pharmacists could reduce over-prescribing of antibiotics both in hospitals and in the wider community.

"There are certain technological supports which would also alert doctors to their prescribing patterns. Some online systems, for instance, ask doctors to justify their choice of prescription and how long the patient is to take the medicine for," he says.

Ultimately, it will take a combined effort from GPs and the public alike to reduce antibiotic consumption. Meanwhile, we await further research to show exactly how such a reduction of antibiotic use would impact on those nasty bugs which are currently resistant to treatment.