A study was conducted to determine the mode of action of antifungal agents in respect to the relationships between the antifungal activities and morphological effects, drug resistance and their effects on the metabolism of pathogenic fungi. The results obtained were as follows :
The antifungal activities and morphological effects of 36 compounds were tested against 8 different strains of pathogenic fungi, such as Trichophyton, Aspergillus, Candida, etc. by the agar plate-streaking method. These compounds can be classified into 6 groups in terms of the relationships between the antifungal activities and morphological effects. Several compounds which showed strong antifungal activity exhibited a griseofulvin-like action on the fungi, a morphologic change. In view of such results obtained, the examination of an in vitro antifungal activity of drugs should be tested in addition to observing any morphologic changes which occur.
The newly isolated strains of fungi were first examined for their susceptibility to nystatin, amphotericin B, trichomycin, variotin and merzonin; Trichophyton mentagrophytes, T. rubrum and Aspergillus fumigatus showed, more or less, differences in susceptibilities to these drugs. The differences in susceptibilities observed may have depended upon the strains employed; A. fumigatus was especially conspicuous in this sense. All of the test drugs employed did not produce a significant degree of increase to resistance in all strains of A. fumigatus tested. The population of the resistant cells of A. fumigatus was determined by the replica plating method. Cells which were highly resistant to amphotericin B or trichomycin were much more numerous than those resistant to nystatin, variotin or merzonin, and the drug resistance of these isolated cells were stable as demonstrated by ten successive transfers on drug-free agar media. Thus, it might be concluded that the pathogenic fungi have a difficulty in acquiring drug resistance to antifungal agents; however, the existence of highly resistant strains and cells may demonstrate the acquisition of an increase in drug resistance, similar to bacteria and other microorganisms, if such drugs were to be used extensively.
The effects of antifungal agents, especially polyene antibiotics, such as nystatin, trichomycin and amphotericin B, and, also, for comparison, pentachlorophenol, a synthetic drug, on the metabolism of Candida albicans or Candida pseudotropicalis were investigated in preliminary experiments in order to determine the primary action of these antifungal agents. The endogenous respiration, the O₂ uptake by the utilization of glucose, the ³²P-phosphate incorporation into the cells and into several kinds of metabolites, and the incorporation of ¹⁴C-amino acids mixture into the cells were examined in the presence of antifungal agents of concentration which inhibited the growth of 50% or more cells. Neither stimulation nor inhibition was observed in the endogenous respiration and the O₂ uptake by the oxidation of glucose in the presence of the employed drugs. The incorporation of ³²P-phosphate into the cells was markedly suppressed by these drugs, especially by the polyene antibiotics. Marked suppression of the incorporation of ³²P-phosphate into the TCA-soluble fraction and a slight inhibition of it into the phospholipid and RNA fractions were demonstrated. The incorporation of ¹⁴C-amino acids into the cells was also inhibited.

抄録全体を表示

Recently there seems to be an increasing tendency in the incidence of human disease caused by the infection with various fungi. This seems to lie in the frequent use of antibiotics and adrenal cortical hormones.
However, severe cases of this disease are mostly unsuccessfully treated with chemotherapeutic agents and their prognosis generally very unfavourable.
It is the purpose of this paper to report human cryptococcosis and to study the effects of antifungal antibiotics and adrenal cortical hormones for the experimental cryptococcosis.
4 cases of cryptococcosis had been observed. Out of those 3 cases were cryptococcal meningitis and one case was generalized cryptococcosis. One case of cryptococcal meningitis and a generalized one were caused by frequent use of large amounts of antibiotics and adrenal cortical hormones.
Therefore, the therapeutic effects of antibiotics and hormone were studied with mortality, cultures of organs, histological findings and C/F ratio of urinary 17-OHCS estimated cy Bongiovanni's method. Cryptococcus neoformans (c.n.) was inoculated intravenously into rats whose weight was 80 to 90 gm. Amphotericin B (A.), Trichomycin (T.), and Nystatin (N.) were injected intraperitoneally into rats and Prednisolone (P.) was used subcutaneously.
(1) Before and after inoculation of 5 × 10⁶ cells of c.n. the animals were injected with P. 50mcg, 5mcg and 0.5mcg/rat/day for 7 days.
(2) After injection of 5 × 10⁷ cells of c.n, intraperitoneal injection of A. at a daily dosage of lmg. per rat, T. and N. at dosage of each 50mcg. were started and continued once a day for 7 days.
(3) Before and after inoculation of 1 × 10⁷ cells of c.n. P. with a dosage of each 50 and 0.5mcg. per rat once a day were given, and after inoculation the animals were treated with T. 50mcg., N. 50mcg. and A. 1 mg/ rat/day for 7 days.
Consequently following results were obtained :
(1) From 4 clinical cases, method and dosis of antifungal antibiotics were observed.
(2) From 2 cases, the frequent use of large amounts of adrenal cortical hormones to the infection seems to cause fungal disease.
(3) When the disease was diagnosed as fungal infection, the use of hormone should be interrupted as possible, followed by the antifungal antibiotics.
(4) As a result on experimence, Amphotericin B was most powerful agent and Trichomycin was next usefull agent for antifungal treatment.
(5) The course of fungal infection was observed C/F ratio of urinary 17-OHCS.

抄録全体を表示

Griseofulvin is exquisitely fungistatic for T. rubrum, while on the other hand, T. mentagrophytes does not have high sensitivity to this antibiotic. Therefore, as Dr. Schwarz suggested, griseofulvin can be used to differentiate these two fungi.
After dissolving 100 mg of griseofulvin in 25 cc of aceton and adding 75 cc of distilled water gradually, the solution of 1000 γ/cc concentration was prepared. Mixing this solution with Sabouraud dextrose agar, 25, 50, 100, and 250 γ/cc of Griseofulvin-Sabouraud agar slants shown Fig. 4 were made. Forty-six strains of T. mentagrophytes and 93 strains of T. rubrum were inoculated on those agar slants and cultivated at room temperature. The observation of their growth and the measurement of their diameter were carried out on the 15th day.
Comparing with the control, although the growth of T. mentagrophytes was inhibited, all the strains formed cultures in each of the various concentrations, even in the saturated medium of over 500 γ/cc. On the contrary, the growth of T, rubrum was markedly inhibited, only one strain developing a culture of 1 mm diameter in 100 /cc and none of the 93 strains showed any growth in 250 γ/cc.
From these observations it is concluded that T. mentagrophytes and T. rubrum may be differentiated readily by the growing results in two weeks on Sabouraud dextrose agar containing over 250 γ/cc of griseofulvin or saturated Griseofulvin-Sabouraud agar.
This method is worth performing as one of the differentiating methods along with others such as pigment production test on corn meal dextrose agar and hair perforation test using in vitro hair culture.

抄録全体を表示

1) Vanbreuseohemの考案による土壌中から好ケラチン性真菌を分離するための所謂hair-baitingtechniqueに於いては, 通常baitとして人の毛髪が用いられているか, 著者らは各種の哺乳動物 (馬・牛・緬羊・山羊・豚・犬・猫・兎・モルモット・ラッテ・マウス) の被毛と人髪とを比較試験した結果, これらの被毛も人髪と同様にbaitとして用い得ることを明らかにした.
2) 東京大学附属家畜病院動物舎の近傍5ヵ所から採取した土壌サンプルについて, 馬の被毛および人髪をbaitとt本法によつて好ケラチン性真菌の存在を調査した : 結果, 全5例のサンプルからMierosporum gypseumが分離され, その中2例からは同時にKeratano-mycesajelloiが分離された.この際κ.ajelloiの発育は一時的に認められたのみで, 間もなくMgypseumによりovergrownされてしまった.またM.gypseumは常に人髪に比して馬の被毛に迅速に旺盛に発育した.動物が飼養もしくは往来する場所の土壌にはケラチン性物質が豊富で, これらの土壌内には好ケラチン性真菌がsaprophytesとして常在することが推定された.なお, 著者らの知る限り,.Mgypseumの土壌からの分離は我国では最初のものである.
3) 供試した土壌サンプルから馬の被毛に発育したM.gypseum全株の菌糸には, 多数の白色小型の球状物が生じ, 形態学的ならびに培養検査の結果, これらは本菌のperfectstageであるcleistotheciaであることが半明した.

抄録全体を表示