GENETIC-ANALYSIS OF HISTOPLASMA-CAPSULATUM STRAINS ISOLATED FROM CLINICAL SPECIMENS IN THAILAND BY A PCR-BASED RANDOM AMPLIFIED POLYMORPHICDNA METHOD

Thirteen strains of Histoplasma capsulatum were isolated from clinical specimens, including those from AIDS patients, in Thailand. Random am plified polymorphic DNA (RAPD) analysis with three different PCR prime rs showed that the DNA fingerprint patterns of the Thai isolates were very similar to each other and homogeneous, with only one exceptional strain, although the patterns were clearly different from those of a r eference North American strain with all primers tested. Although the d ifference in the DNA fingerprinting patterns was minor, Thai isolates could be classified into two to four groups, A common PCR band (about 700 bp) in the patterns of all H, capsulatum strains was extracted, an d its DNA sequence was determined. A new PCR primer set for the identi fication of H. capsulatum species was developed based on this sequence information. This primer set was 100% successful in the identificatio n of the reference strain as well as all Thai isolates. The results of specificity tests of the primer set far the identification of the fun gus are also discussed.