Abstract

A comparison has been made of Lowenstein-Jensen medium, with or without added pyruvate, 7H11 oleic acid-albumin agar slopes made selective by the addition of antibiotics, and selective Kirchner medium in the isolation of tubercle bacilli from specimens other than sputum. A combination of a standard mild preliminary treatment with sulphuric acid and selective medium reduced the contamination rate to 0·1%. Neither acid treatment nor antibiotics appeared to reduce the isolation rate. An effective procedure is to treat all specimens (except cerebrospinal fluid) with acid and culture on two Lowenstein-Jensen slopes (one with pyruvate), a 7H11 selective slope, and in two bottles of selective Kirchner medium.