1967 Volume 40 Issue 12 Pages 445-453
A Salmonella paratyphi B, isolated from a febril paratyphoid patient at the initial stage of chloramphenicol treatment, was proved to be drug sensitive and of phage type 3a. An organism was again isolated from the same patient in his convalescence. It was also Salmonella paratyphi B, but this time was proved to be resistant to such drugs as chloramphenicol, tetracycline, streptomycin, sulfonamide and aminobenzyl penicillin and have a phage type belonging to none of hitherto known lytic patterns.
It was ascertained that its drug resistance was transmissible to drug sensitive Escherichia coli by mixed culture (1st transmission), and the further transmission (2nd transmission) was also possible. Consequently, it was considered to be controlled by “resistance transfer factor (R)”.
From the results of the drug inactivation test, it was suggested that the resistance to aminobtenzyl penicillin and to chloramphenicol was attributable to the acquirement of productivities ofβ-lacatmase against penicillin and of chloramphenicol-inactivation respectively.
Furthermore, an increase in the productivity of cephalosporinase was noted in accordance with the development of the productivity of β-lactamase against penicillin.
