In vitro comparison of terbinafine and itraconazole against Penicillium marneffei.

We evaluated terbinafine and itraconazole against 30 isolates of Penicillium marneffei using a modification of the National Committee for Clinical Laboratory Standards broth macrodilution MIC testing protocol for yeasts. The minimal fungicidal concentration (MFC) was determined by plating 100 microl from each MIC drug dilution having no growth onto Sabouraud glucose agar incubated at 30 degrees C. The MFC was the dilution at which growth was absent at 72 h of incubation. The MICs, in micrograms per milliliter, were as follows: terbinafine, 0.03 to 1.0 (geometric mean titer, 0.09); itraconazole, 0.03 to 0.5 (geometric mean titer, 0.04). The MFCs, in micrograms per milliliter, were as follows: terbinafine, 0.03 to 8 (geometric mean titer, 2.60); itraconazole, 0.03 to 8 (geometric mean titer, 2. 45). Primary fungicidal activity (MFC within 2 dilutions of MIC) was observed with terbinafine in eight isolates and with itraconazole in four isolates. The data indicate that terbinafine is active against P. marneffei in vitro and may have a previously unrealized role in the management of infections caused by this fungus.

Identification of genetic variation among St. Louis encephalitis virus isolates, using single-strand conformation polymorphism analysis.

A single-strand conformation polymorphism (SSCP) technique was developed for identification of genetic variation among 26 isolates of St. Louis encephalitis (SLE) virus. A 750-bp portion of the envelope gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR) and the products analyzed by SSCP. SSCP reliably identified genetic variation among the isolates from the US, Central and South America. Closely related isolates from a smaller geographic area (Panama) were also distinguishable by SSCP. The sensitivity of this technique was demonstrated by sequencing each of the isolates used; SSCP was capable of discriminating between isolates that had as few as 1-6 nucleotide differences. These results indicate that SSCP has excellent potential as a tool to screen rapidly SLE virus isolates for genetic variation and could be incorporated into molecular epidemiology studies.