Abstract
While it is well known that many of the dysenteric infections of the far South are caused by Endamoeba histolytica, there undoubtedly are a considerable number of cases in which this protozoon has no etiologic relationship. In such cases, we find some one of the strains of B. dysenteriae playing the sole causal rôle. It was first suggested to Doctor C. W. Duval by Doctor Simon Flexner (personal communication) that the bacillary dysentery incidence should be determined for the New Orleans area, particularly as this region presents at all times many cases of amebic colitis.
Material for this study was obtained from approximately 100 sporadic cases of dysentery in which no protozoa or other animal parasites were detected in the dejecta. The clinical aspects of these cases have been previously reported. 1 The group comprises acute, subacute, and chronic forms of the disease. The specimens, with few exceptions, were fresh bowel scrapings obtained directly by means of proctoscopic examination. Fletcher and Jepps 2 pointed out that material for bacteriologic studies obtained in this manner is far more desirable than the stool, because the likelihood of culturing the causal agent is greatly enhanced. Plating of the fresh mucosal scrapings was carried out in the usual way and suspected colonies of B. dysenteriae transferred to differential culture media. The recovered dysentery cultures were further identified with respect to strains and then tested with homologous immune sera and the serum from the particular case to determine etiologic relationship.
Bacteriologic investigations into the cause of acute infectious dysentery have been thoroughly studied for epidemic outbreaks in the United States by Flexner and his coworkers, 3 and distinct strains of the Shiga bacillus have come to be recognized.
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