VI - GENETIC-HETEROGENEITY IN HUMAN-DERIVED PNEUMOCYSTIS-CARINII

Genetic heterogeneity has been observed among isolates of human-derive d Pneumocystis carinii (P. carinii sp. f. hominis). DNA sequence analy sis has been shown to be informative in distinguishing between isolate s of P, carinii sp. f hominis. Single base polymorphisms have been obs erved in the genes encoding the mitochondrial large subunit ribosomal RNA, the mitochondrial small subunit ribosomal RNA and the AROM protei n. The highest level of genetic variation has been found at the intern al transcribed spacer (ITS) regions of the nuclear ribosomal RNA opero n. Typing of isolates of P. carinii sp. f. hominis has enabled the exa mination of the frequency of different types of P. carinii sp. f, homi nis in distinct populations. It has also facilitated studies on the ac quisition and transmission of P. carinii sp. f. hominis infection. (C) 1998 Federation of European Microbiological Societies. Published by E lsevier Science B.V. All rights reserved.