Salmonella Typhimurium infection in Mice Treated with Niridazole

Groups of mice were infected with two strains of Salmonella typhimurium. Those infected with the less virulent strain no. 8 were treated with niridazole in doses of 200 or 600 mg per kg. Those infected with strain no. 12 received either 100 or 400 mg per kg. Compared with non-treated control mice the treated groups showed significantly higher numbers of survivors. In the group infected with strain no. 8 no difference was found in the incidence of survivors between the 200 and 600 mg per kg treatment groups. Such a difference was noted, however, in the case of strain no. 12 between the 100 and 400 mg per kg groups. Bacterial counts of spleens of survivors showed that treatment with niridazole significantly reduced the numbers of bacteria as compared with control mice.

In-vitro testing with impregnated disks was found to be effective in determining sensitivity of salmonella strains. Of 212 strains of S. typhi 178 gave zone sizes of 13 mm or greater. Of 77 other miscellaneous salmonella strains 67 had zone sizes of this order. It is essential that disk tests be done with freshly prepared niridazole solutions.

It is suggested that niridazole may be worthy of trial in cases of chronic salmonellosis that are unaffected by chloramphenicol and ampicillin. It may also be worth while to evaluate its use in chronic enteric carriers.