In the course of oral administration of the medicine consisting of live multiple-antibiotics-resistant streptococcus fecalis to healthy men, those organisms were frequently found alive in their feces.
Thereby, untoward symptoms, subjective or objective, such as disorder of defecation or abnormalities in stool findings, have not been encountered at all.
Furthermore, in the course of combined administration with several kind of antibiotics used, the intestinal bacterial alteration-an well-known phenomenon which is said to frequently occur under the influence of antibiotics-has never been observed yet.

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The recent bacillary dysentery in this country can be characterized by such a trend as becoming milder, while tending more often to occur in the form of massive outbreak due to antibiotic-resistant bacilli.
It can be presumable that some changes occur in the biological properties of bacteria as a result of the acquisition of drug-resistance, which should possively be attributable to the recent trend of bacillary dysentery. In this respect, the following experiments were carried out.
By means of the stepwise selection method previously reported, using the media containing various concentrations of chloramphenicol, chlortetracycline and dihydrostreptomycin sulfate, twelve strains of Shigella which were originally sensitive to above drugs were made resistant to that of increasing concentrations.
After their resistance reached to 100 γ/ml antibiotic concentration level, their biological properties were contrasted with that of the original sensitive ones.
1) Virulence test
Bacterial suspensions of the sensitive and resistant strains in the amount of 0.1mg, 0.5mg, 1.0mg, and 5.0mg respectively were injected into the abdominal cavities of 4 weeks old dd-strain mice weighing 14 gm, and the rate of mortality was compared.
The bacterial quantity for LD₅₀ was greater in the resistant group than in the sensitive one, and this would indicate that with the increase of antibiotic resistance the virulence tend to become weaker.
2) Vitality test
One drop of each bacterial suspension from capillary pipette was added to 50 ml of distilled water, physiological saline solution and well water respectively. These were then incubated at 30°C. On each successive day afterwards, the liquid was cultured on the solid media and bacterial survival was examined. In this manner, the surviving term of bacteria was measured.
The surviving term would be, the Author views, one of the most tangible manifestations of the vitality of bacteria.
The test showed the days of survival were longer, i. e. the vitality is greater, in the resistant strains than in the originally sensitive ones.
Considering above findings, it may be reasonably concluded that the dysentery bacilli tend to be weakened in its virulence by developing the resistance to antibiotics, and, at the same time, tend to enhance the surviving term, the vitality.

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Lincomycin which has a striking similarity in antibacterial spectrum to macrolides was employed for the treatment of bacillary dysentery with the following results:
1) The drug M I C for shigellas ranged from 125 to 500 mcg/ml.
2) Lincomycin concentrations in stools determined at about 20 hrs. after an oral dose of 250-500 mg were 600-700 mcg/g.
3) Lincomycin therapy was commenced 2 to 12 days after onset of the disease in 18 patients bacteriologically positive, with or without symptoms, for shigellas resistant to usual antidysenteric antibiotics. With 250-1, 000 mg of oral lincomycin daily, 16 of the 18 patients had complete elimination of the causative bacilli in 5 days, while only 2 showed a sign of bacillary reemergence.
4) This antidysenteric capability of lincomycin stands comparison with, or rather exceeds, that of macrolides.
5) Further clinical experiments will be required for a definite conclusion, but it may be safe to say at this stage that oral lincomycin has shown a significance as a prospective remedy for bacillary dysentery caused by shigellas resistant to conventional antibiotics.

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