The World Health Organisation is to meet next week to consider the growing threat from a sexually transmitted infection which has developed resistance to most known antibiotics.
Gonorrhoea is the second most common sexually transmitted disease in the UK after chlamydia with 16,629 cases recorded in 2008. Anecdotal reports of resistant cases from around the country suggest the infection could become "extremely difficult to treat", according to Professor Cathy Ison of the Health Protection Agency's Centre for Infection.
The WHO meeting is the first to be held on gonorrhoea and an indication of the scale of the global threat, Professor Ison said. Worldwide, there are more than 6 million cases a year. "In Japan they have had patients who have failed therapy and a number of other countries have been affected. In the UK we have seen an increase in reports to the National Reference Laboratory [for sexually transmitted bacteria] indicating that these bacteria are becoming less susceptible. We think we are starting to see failures of treatment here. It is a cause for worry," Professor Ison said.
If left untreated, gonorrhoea can cause pelvic inflammatory disease, ectopic pregnancy and infertility in women. Current treatment is with a single dose of antibiotics, orally or by injection, which is normally enough to clear up the infection and prevent its being passed on.
Resistance to antibiotics emerges with all bacteria over time but gonorrhoea is a "particularly clever little bug," which has become progressively harder to treat over the decades, Professor Ison said.
Between 2003 and 2005, the standard treatment with the antibiotic ciprofloxacin was phased out and replaced with the newer class of antibiotics called cephalosporins. Now doctors are running out of options. They are being forced to use less effective drugs to which there is no resistance. But these prolong the treatment, increasing the risk of onward transmission (if the patient has sex with new partners).
Professor Ison said: "What we need to do at the WHO meeting is come up with a different strategy for treatment. At the moment we use a single drug. We may need to use two drugs at the same time or one over a number of days. We also need to improve the ways we communicate with other countries so we know what is happening in other parts of the world."
Britain has one of the highest rates of gonorrhoea in Europe. Professor Ison said the reason was unclear but that it could be because of better reporting. "Choosing an effective antibiotic can be a challenge because the organism that causes gonorrhoea is very versatile and develops resistance to antibiotics very quickly. Penicillin was used for many years until it was no longer effective and a number of other agents have been used since.
"There are few new drugs available and so it is probable that the current use of a single dose may soon need to be revised and treatment over several days or with more than one antibiotic will need to be considered. If this problem isn't addressed then there is a real possibility that gonorrhoea will become a very difficult infection to treat," she said.
"The infection could be avoided if people practised safe sex," she added.