Background and objective: The absence of culture methods to recognize the presence of resistance to sulfa or sulfone drugs in Pneumocystis jiroveci has led to develop molecular techniques based on the identification of mutations in the dihydropteroate synthase gene (DHPS). The aim of this study was to determine the frequency of these mutations in our geographical area, since in Spain there is no information concerning this issue.
Patients and method: The study included all Pneumocystis pneumonia cases identified in our hospital during two years. Diagnosis was made by nested PCR in bronchoalveolar lavage samples. DHPS-3 and DHPS-4 primers were used to amplify the DHPS gene and mutations associated with sulfa resistance were identified using a restriction fragment length polymorphism assay.
Results: In 9 out of the 12 cases identified, DHPS could be amplified (75%) from which 3 (33.3%) showed some mutation linked to sulfa resistance.
Conclusions: In our area, we have found a relatively high frequency of pneumonia caused by P. jiroveci's strains with mutations associated with sulfa resistance.