Dihydropteroate synthase (DHPS) genotyping by PCR-RFLP analysis of Pneumocystis jirovecii repeated isolates from HIV-infected patients: A preliminary study

摘要

Pneumonia caused by Pneumocystis jirovecii (PcP). fomierly named Pneumocystis carinii f. sp. hominis. remains an important opportunistic infection in AIDS and other immunoconipromised patients, although widespread PcP chemoprophylaxis and highly active antiretroviral therapy (HAART) have reduced the incidence of this disease. Sulpha drugs, mainly the combination trimetoprim/ sulfamctozaxole (co-trimoxazole), are considered to be the key agents in treatment and prophylaxis of this infection. Animal studies have shown that the major target for co-trimoxazole is the enzyme dihydroptcroate synthase (DHPS) a component of the folk acid biosynthesis pathway. Point mutations, at codons 55 and 57, in the DHPS gene of P. jirovecii isolated from AIDS patients have been reported in several studies and linked to prior exposure to sulpha drugs, suggesting possible emergence of sulpha drug resistance . The aim of this study was to determine the DHPS genotype of R jirovecii isolates from repeated induced sputa by PCR-RFLP analysis, in order to assess the stability of the DHPS genotypes.