On the cultivation and biological characters of Leishmania tropica / I.J. Kligler.

  • Israel Jacob Kligler
Date:
1924
Catalogue details

Licence: Public Domain Mark

Credit: On the cultivation and biological characters of Leishmania tropica / I.J. Kligler. Source: Wellcome Collection.

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    of oxygenated blood. If the culture remains free from con- taminating organisms, the color of the medium darkens at the bottom, but the zone near the top remains bright red. Con- taminating organisms bring about changes in the color of the blood, hemolysis, ete., which can be easily detected after three or four days. Such tubes may be discarded, since Leishmania tropica rarely grows in the presence of contaminating bacteria. Tubes which remain free from bacteria gradually undergo hemoly- sis, and a positive culture can almost invariably be recognized by the bluish black appearance of the medium and the watery bluish tint of the paraffin oil when looked at from above. In positive cultures flagellated forms may be found, by careful darkfield examination, on the third or fourth day. If the inocu- lated material contained only a few organisms, a week or more may elapse after inoculation before the parasites can be detected by darkfield examination. In fresh cultures the various flagellated forms described by other observers are noted; as the culture ages more and more ovoid forms are seen, and in old cultures the typical non- flagellated ovoid parasites, such as are found in the lesion, are encountered. The organisms are particularly abundant in bits of fibrin, large colonies being entangled in the fibrin network, which seems to offer a favorable substratum. Leishmania tropica is an obligatory aerobe. Experiments made with different oxygen tensions showed that active con- tinued growth can be obtained only at normal oxygen tension. Under anaerobic conditions no growth is obtained. Paraffin oil does not modify the aerobic condition of the medium. Leishmania tropica is very sensitive to changes in reaction. At pH 7.8 and 6.6, respectively, there was no growth at all. Growth was obtained in the range from pH 7.0 to 7.6 but was best at pH 7.2. The tests were made in media of which the reaction was adjusted by means of HCl and acetic acid, unbuffered, and buffered with phosphate, always with the same results. Positive cultures were obtained from three cases. All the negative cultures were contaminated with staphylococci. Of
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