Denis Mitchison

Mitchison finally stopped regular work at the age of 95. He died in Kingston in July 2018 at the age of 98 of bilateral pulmonary embolism.

After his notional retirement in 1985, he continued working first at the Royal Postgraduate Medical School, Hammersmith and then at St George's, University of London. He developed the technique of measuring the early bactericidal activity of drugs, which is now standard practice as the initial step in the phase II of clinical development of new drugs with Amina Jindani and colleagues in South Africa. He also introduced the concept of the 8-week phase II study with the proportion of patients obtaining negative sputum culture at 8 weeks, a standard assessment in most such studies. More recently he developed a new type of phase II 8-week study using modelling of counts of TB in sputum during treatment (with Geraint Davies and the South African MRC). He worked on several new anti-TB drugs and participated in clinical trials on high dosage rifamycins.

Starting with a publication in 1970, the second phase dealt with the shortening the treatment period from at least 12 months to 6 months by using rifampicin and pyrazinamide in so-called "short-course" regimens which have been the basis of current standard therapy with 2 months of 4 drugs (rifampicin, isoniazid, pyrazinamide and ethambutol) followed by 4 months of rifampicin and isoniazid.

Following the decisive importance of drug-resistant tubercle bacilli in treatment, he was appointed in 1964 as director of a new MRC Unit on Drug Resistance in Tuberculosis (later changed to MRC Unit for Laboratory Studies of Tuberculosis) at the Royal Postgraduate Medical School. He then worked closely with D'Arcy Hart at the MRC TRU and later with Wallace Fox, director of the MRC Tuberculosis and Chest Diseases Research Unit, on developing effective treatment for TB at a cost sufficiently low to be affordable in developing countries.

In 1954 Denis Mitchison's mother wrote the fantasy book Graeme and the Dragon, in which the protagonist is her grandson, Denis's son Graeme Mitchison.

He was educated at the Dragon School, Oxford, and Abbotsholme School, going on to Trinity College, Cambridge, where he studied natural science, obtaining a 1st class degree and a senior scholarship. He only then changed to medicine, qualifying from University College in 1943, and chose postgraduate training in pathology.

Denis Anthony Mitchison CMG (6 September 1919 – 2 July 2018) was a British bacteriologist.

Mitchison was born in Oxford in 1919, the son of the Labour politician Dick Mitchison and his wife, the writer Naomi (née Haldane). His uncle was the biologist J.B.S. Haldane and his grandfather the physiologist John Scott Haldane. His younger brothers are the zoologists Avrion Mitchison and the late Murdoch Mitchison.