UPDATE ON PNEUMOCYSTIS-CARINII F SP. HOMINIS TYPING BASED ON NUCLEOTIDE-SEQUENCE VARIATIONS IN INTERNAL TRANSCRIBED SPACER REGIONS OF RIBOSOMAL-RNA GENES

Pneumocystis carinii f. sp. hominis isolates from 207 clinical specime ns from nine countries were typed based on nucleotide sequence variati ons in the internal transcribed spacer regions I and II (ITS1 and ITS2 , respectively) of rRNA genes. The number of ITS1 nucleotides has been revised from the previously reported 157 bp to 161 bp. Likewise, the number of ITS2 nucleotides has been changed from 177 to 192 bp. The nu mber of ITS1 sequence types has increased from 2 to 15, and that of IT S2 has increased from 3 to 14. The 15 ITS1 sequence types are designat ed types A through O, and the 14 ITS2 types are named types a through n. A total of 59 types of P. carinii f. sp. hominis were found in this study.