Lloyd Conover
Inventor of tetracycline, used to treat a wide range of infections
LLOYD CONOVER, who has died aged 93, created the antibiotic tetracycline in 1952, providing the medical establishment with a new line of defence against virulent and potentially deadly infections.
Ever since Alexander Fleming had discovered penicillin in 1928, scientists had been working hard to find new antibiotics. Chlortetracycline, purified from a bacterium found in soil, was rushed into production in 1948, while penicillin derived from overripe melon proved effective in treating thousands of soldiers during the Second World War.
As the cost of penicillin dropped sharply, the pharmaceutical company Charles Pfizer & Co recruited pilots, explorers and ordinary citizens to send in soil samples from all over the world for testing. Conover, meanwhile, was more interested in the molecular structure of the drugs already to hand. Under carefully controlled conditions, he stripped chlortetracycline of its chlorine atom and replaced it with a hydrogen atom.
The result was tetracycline, the first new antibiotic to be created by chemical modification in the lab. Such a feat had previously been considered impossible as it was thought that any fundamental change to a natural antibiotic would destroy its therapeutic qualities.
Conover’s discovery ushered in a new era; today, virtually all antibiotics are modified to improve their efficacy or to reduce the number of undesirable side-effects. By 1955, tetracycline was the most widely prescribed antibiotic in America. It proved effective at tackling a range of infections found in both humans and animals, such as pneumonia and the tick-borne Lyme disease.
Chickens, pigs and cows given feed laced with tetracycline stayed healthier than their untreated counterparts, and fruit farmers sprayed their trees with tetracycline to protect them from disease. Tetracycline has also been used as the recommended treatment for acne, sexually transmitted infections like chlamydia and more immediately dangerous illnesses such as cholera.
As time went on, however, scientists began to express concern at the widespread use of antibiotics in agriculture, which has helped to fuel the rise in drug-resistant infections. Just two years after tetracycline was patented, a treatmentresistant strain of shigella – which causes more than 160 million cases of severe diarrhoea every year – came to light. In an effort to combat the problem, Britain prohibited farmers from using tetracycline to help their animals gain weight. In Denmark a blanket ban on using antibiotics for “nontherapeutic” purposes in farm animals came into force in 1999.
Lloyd Hillyard Conover was born in Orange, New Jersey, on June 13 1923. Aged 18 he won a place at Amherst College in Massachusetts to study Chemistry, but the Second World War intervened. He spent three years serving in the Pacific with the US Navy before returning to education, receiving his doctorate from the University of Rochester in 1950.
In 1971 Conover became the director of Pfizer’s research laboratories at Sandwich, Kent. In addition to his work on tetracycline, he played a leading role in the development of pyrantel and morantel, which are used to destroy parasitic worms in humans. He ended his career as senior vice president for agricultural products research and development.
In 1992 he was inducted into the National Inventors’ Hall of Fame. At the time only 98 other scientists, among them Alexander Graham Bell and the two Wright brothers, had received the honour.
Lloyd Conover’s first wife Virginia (née Kirk) predeceased him in 1988. He married, secondly, Marie Solomons; she died in 2003. In 2006, aged 82, he married Katharine Meacham. She survives him, as do four children from his earlier marriages.