TB Test "Could Save Lives"

A way of identifying dangerous antibiotic-resistant TB bacteria has been developed in Britain. The test -- developed by the Public Health Laboratory Service (PHLS) -- can analyze the genetic profile of bacteria to see if they are among those that have adapted to fight key drugs.

Approximately 6 percent of TB cases in the UK involve bacteria that have developed resistance to Isoniazid or Rifampicin, the principal antibiotics used to treat TB. The rate in some other parts of the world is far higher, but London and other UK cities have a rising proportion of disease-resistant cases.

The standard time it takes to test bacteria by growing a culture is two to four weeks. After that, it takes the PHLS 10 to 14 days to check the bacteria for resistance. With the new method, this second half of testing can be done in one or two days.

The shortened time frame allows doctors to prescribe effective medication to patients more swiftly and to test people with whom they have been in contact, but who have not yet developed the disease. The developers are hopeful that they will eventually be able to shorten the initial waiting time with a test that can be carried out on the sputum of a patient.

Professor Francis Drobniewski of the PHLS Mycobacterium Reference Unit told the BBC, "The tests correctly identified three-quarters of Isoniazid-resistant isolates. The main advantage is that doctors can work out who had drug-resistant TB and give them the most effective medicine. This is important, particularly in the case of patients who are immunosuppressed, such as those who are HIV-positive or who are undergoing cancer treatment."

According to Drobniewski, the new method is not more expensive to carry out than existing tests. The results of the evaluation of the new test will be revealed at the PHLS annual conference in Warwick next week.

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