Hydrogen sulphide production by bacteria.

Hydrogen sulphide production by growing cultures and non-multiplying suspensions was compared and the factors influencing the sensitivity of the tests were investigated. Cysteine hydrochloride (0.01 yo) was added to Lemco broth to provide a medium with a standard source of sulphur. H,S was detected with lead acetate papers more readily than by lead acetate agar. Suspensions were tested with cysteine, sodium thiosulphate and sodium sulphite ; the organisms investigated were mainly Bacteriaceae and seldom failed to produce H,S from cysteine ; sodium thiosulphate was less readily attacked ; sodium sulphite was unsuitable for this technique. Media commonly used for testing the capacity of bacteria to produce H,S are reviewed and the value of this test in bacterial classification discussed.