Effect of pyridines on phenotypic properties of Bordetella pertussis

Abstract

Several conditions of growth of B. pertussis cause a reversible phenotypic alteration in properties termed modulation. Growth in medium containing nicotinic acid induces normal (X-mode) cells to change to modulated (C-mode) cells. Several pyridines and compounds resembling pyridines were examined for their ability to affect modulation, using envelope protein patterns and serological reactivity as indicators of modulation. 6-Chloronicotinic acid and quinaldic acid were more effective modulating stimuli than was nicotinic acid on a molar basis. Both 2-chloronicotinamide and isoniazid interfered with nicotinic acid-induced modulation and can be called antimodulators. Picolinic acid inhibited growth.