ON THE DESOXYCHOLATE‐SENSITIVE STRAINS OF SALMONELLA PULLORUM

Low expression of AcrB in the deoxycholate-sensitive strains of Salmonella enterica subspecies enterica serovar Pullorum

“…The morphological, biochemical, serological, and pathogenic properties of the deoxycholate‐sensitive (DCs) strains of S . Pullorum, isolated from chickens on a farm near Tokyo in 1958 (1), did not differ from the deoxycholate‐resistant (DCr) strains commonly isolated in the field on media containing bile salts (3). In one study, DCr mutants were easily isolated from the DCs isolates in the presence of deoxycholate, at frequencies of 10 6 (1).…”

“…Around 1960, strains of Salmonella enterica subspecies enterica serovar Pullorum, which were susceptible to deoxycholate, were isolated in different areas of the world, including Japan (1) and the United Kingdom (2). These strains did not grow in media containing bile salts commonly used for the isolation of Enterobacteriaceae .…”

“…This suggested that these bacteria may acquire reduced susceptibility to bile salts endogenously. In addition, the DCs strains differed from the DCr strains in that they were highly sensitive to certain antibiotics, chemotherapeutics, dyes, and anionic and cationic surface‐active agents (1). This finding suggested the presence of multi‐drug efflux systems in these bacteria.…”

“…In the present study, we investigated the mechanism responsible for bile susceptibility in the DCs strains isolated in 1958 in Japan. Three DCs strains of S. Pullorum, A651, A900 and A537, and a DCr strain, A521, were used in the present study (1). The minimum inhibitory concentration (MIC) of deoxycholate (sodium deoxycholate; Wako Pure Chemical Industries, Tokyo, Japan) was determined in the presence and absence of phenylalanine arginine β‐naphthylamide (PAβN, 10 mg/L) by a broth dilution method, according to the Clinical and Laboratory Standards Institute recommendations (4).…”

Biochemical Differentiation of Salmonella gallinarum and Salmonella pullorum cultures

“…The isolation of the strains was made mainly on plain agar; selective media were not used for two reasons, one that many S. gallinarum-pulloruni strains exhibit a peculiar sensitivity to bile and bile salts and develop poorly or not at all on media with such ingredients (21,26) and two, that these germs were sought in products (bone, liver, joint, ovaries/testicles) where a complex flora was not likely to be found, and thus a selective action of the media was not necessary. After isolation, the cultures were streaked on lactose-bromthymol blue-agar to obtain isolated colonies.…”