Bacteriological examination of feces

Abstract

From the tests made using comparatively the media of enrichment, hyposulfite broth, with the modifications introduced by Shäffer and Kauffmann, and a glycerine solution, the authors verified that the best method of preservation and enrichment is that of glycerine, as this gave 41,1%  positive results, while with the
Shäffer's medium there were obtained only 31,1% positive results. When confronting the glycerine with the Kauffmann's medium, there were obtained 31,4% positive results for the first and 14,6% for Kauffman's medium. The glycerine tested comparatively with the Leifson's Selenite F. enrichment medium gave better results for the isolation of Eberthella typhosa, as there were obtained 12,2% positive results when using the glycerine, while there were found to be only 10,3% positive results for the F. medium. The influence of the temperature was observed when using the glycerine methods, there having been noticed that the temperature of 20°C showed better results than that of 37°C. A second plating after 24 hours is of great advantage, as this gave an increase of 12,2% in the results obtained. As isolation medium there were used Drigalsky, Endo, the Wilson and Blair's bismuthe medium, desoxycholate-citrate agar (Leifson), eosin-methylene-blue-agar of Teague and Clurman and the rosolic-acid agar medium recommended by Rangel Pestana an Calazans. The desoxycholate-citrate agar medium is studied comparatively with the rosolic-acid agar medium (Calazans and Pestana) and eosin-methylene blue agar (Holt, Harris and Teague). The authors conclude that the desoxycholate-citrate agar is a good medium for the isolation of Shigella paradysenteriae Hiss-Roussell and Flexner types, it being even necessary to use other differential media in order that the results of the bacteriological diagnosis of the dysenteries may not be incomplete. For identification there was used Krumwiede's triple sugar medium, and the modification by Klinger. The semi-solid medium of Hiss, the modified formula of which is used in the "Instituto Bacteriológico de São Paulo" (Bacteriological Institute in São Paulo),
carbohydrates being added for the identification of isolated germs, is recommended, the rosolic acid being preferred as indicator. For the identification there was used the classification given in "Bergey's Manual of Determinative Bacteriology", 4th. edition,1934. Of the 9.810 feces examined, 6.719 were from with intestinal disturbances, and 3.091 from stools sent for the examination of carriers. Tables n^o 1 and 2 show the results obtained by the authors during 9 years of work (form 1932 to 1940). Of the genus Shigella, Shigella dysenteriae (Shiga) was found in 112 instances and Shigella ambigua in 53. In the group of Shigella paradysenteriae, out of the three varieties admitted by Bergey, there were found the following: Hiss-Roussell (764 strains) and Flexner (256 strains). The authors did not find the Strong variety during all the time in which the examination were made. The Shigella paradysenteriae, Hiss-Rouseell variety, was the most frequent, 11,3%  following the Flexner with 3,5% , calculated
for the total of examined feces (6.719). In the Shigella alkalescens-dispar group there were included all the species that do not ferment lactose and which in the Hiss series behaved in the same manner, differing only by the tornesoled milk. In the Shigella sonne group, there were joined all those fermenting lactose, according to Bergey's classification, waiting still for a better identification and a study of the species there included. In the genus Salmonella, Gram-negativ bacilli, mobile, are included, classified according to Bergey (1934), but only those which do not produce indol, not liquifying gelatine and do not ferment lactose, saccharose and salicine. In this group there are included principally the Salmonella paratyphi, Salmonella schottmülleri, Sallmonella typhimurium, Salmonella interides, and Salmonella aertriycke, and other species, which shall be studied later according to Kauffmann's scheme. There were not included in this group, as they produce indol, the Salmonella morganii, Proteus morganii in Bergey's classification (1940), Salmonella columbensis (Bacterium columbensis), described also under the denomination of Salmonella. pauloensis. These germs are very commun, frequently found in stools and in water. The Salmonella are very rare, as in 9.810 feces examinations the authors have isolated these in only 34 instances, 6 of which were
found in stools of carriers. In the feces of carriers the authors had 548 positive examinations for Eberthella typhosa, there following the Shigella paradysenteriae, Hiss-Roussell variety, with 28 positive results.