Action of o-Iodosobenzoic Acid on Certain Bacteria

Although o-iodosobenzoic acid was studied with regard to its bactericidal action by Loevenhart and Grove 1 there seems to have been little if any work done on this subject since then. These authors presented, along with their results pertaining to physiological effects, evidence that o-iodosobenzoic acid and related compounds had definite in vitro bactericidal action upon organisms of the colon group including B. typhosus and upon B. pyocyaneus and Staphylococcus aureus. Bacteriological studies in vivo were not performed. Sodium o-iodosobenzoate was found to be highly toxic to the animal organism when administered subcutaneously and intra-peritoneally.

Recent work has indicated that o-iodosobenzoate at _pH 7 may be used for the quantitative estimation of -SH groups whether in compounds such as cysteine and glutathione 2 or in proteins such as denatured hen's egg albumin and urease 3 , 4 according to the process:

While the following experiments can in no sense be considered as final, the evidence at hand suggests there may be a correlation between the reproduction and survival of certain bacteria and the presence of -SH groups (cf. 5 , 6 ) although it is recognized that iodosobenzoate is not entirely specific for the sulfydryl group. Irrespective of theory it may prove worthwhile to study further the possible use of locally applied o-iodosobenzoic acid in the treatment of infected wounds. The work is presented in its present stage since the author will not be able to do further experimental work for the duration.

Experiments with E. coli. With Fildes synthetic ammonium lactate medium and concentrations of organisms of about 1000/cc it was found that o-iodosobenzoate in a concentration of 0.5 mg % completely prevented growth for as long as 72 hr, and as growth was not obtained on replating it was concluded that the effect was catericidal rather than bacteriostatic. Sulfanilamide controls showed definite growth after replating. A concentration of 1.0 mg % completely inhibited the growth of as many as 5 × 10⁷ organisms per cc while 0.25 mg % permitted only very slight growth of 5 × 10 3 organisms per cc after 48 hr.