a1 Enteric Reference Laboratory, Public Health Laboratory Service, Colindale Avenue, London, NW9 5HT
Transferable chloramphenicol resistance has become common in the typhoid bacillus in countries such as Mexico, India, Vietnam and Thailand. Situations such as this, and others analogous to it in many parts of the world, are the result of the long-term indiscriminate use of chloramphenicol and other antibiotics in the affected areas. They can be rectified only by more rational antibiotic usage.
(Received November 23 1974)