Pneumocystis jiroveciDihydropteroate Synthase Genotypes in Immunocompetent Infants and Immunosuppressed Adults, Amiens, France

Abstract

To date, investigations of Pneumocystis jiroveci circulation in the human reservoir through the dihydropteroate synthase (DHPS) locus analysis have only been conducted by examining P. jirovecii isolates from immunosuppressed patients with Pneumocystis pneumonia (PCP). Our study identifies P. jirovecii genotypes at this locus in 33 immunocompetent infants colonized with P. jirovecii contemporaneously with a bronchiolitis episode and in 13 adults with PCP; both groups of patients were monitored in Amiens, France. The results have pointed out identical features of P. jirovecii DHPS genotypes in the two groups, suggesting that in these two groups, transmission cycles of P. jirovecii infections are linked. If these two groups represent sentinel populations for P. jirovecii infections, our results suggest that all persons parasitized by P. jirovecii, whatever their risk factor for infection and the form of parasitism they have, act as interwoven circulation networks of P. jirovecii.

Prospective Multicenter Study of Pneumocystis jirovecii Colonization among Cystic Fibrosis Patients in France

“…Whether Pneumocystis colonization could have a role in the natural course of CF lung disease has not been demonstrated so far, but the role of CF patients colonized by P. jirovecii as a reservoir and as infective sources of this microorganism for other susceptible individuals can be strongly suspected (28,29), which is consistent with the continuous infection-andclearance cycle involving P. jirovecii recently reported in CF patients by Montes-Cano et al (18).…”

NosocomialPneumocystis jiroveciiinfections

“…It is assumed that these mutations result in reduction the affinity of DHPS with receptors for sulfonamides and therefore in lower sensitivity or even resistance of mutant P. jirovecii organisms to these drugs. Prior exposure to sulfonamide drugs has been identified as a predictor of mutant genotypes (reviewed in Totet et al, 2004). In addition the city in which a patient resides has also been identified as an independent risk factor (Huang et al, 2000;Kazanjian et al, 2000), a factor that supports the hypothesis that P. jirovecii is transmitted from infected treated patients to susceptible untreated patients, either directly or through a common envi-ronmental source.…”

“…In addition the city in which a patient resides has also been identified as an independent risk factor (Huang et al, 2000;Kazanjian et al, 2000), a factor that supports the hypothesis that P. jirovecii is transmitted from infected treated patients to susceptible untreated patients, either directly or through a common envi-ronmental source. Totet and colleagues identified P. jirovecii genotypes at the DHPS locus in immunocomptetent infants with primary infection and immunosuppressed adults with PCP (Totet et al, 2004). Both groups of patients were monitored in the same city.…”

“…The results of recent studies based on observations of PCP case clusters combined with P. jirovecii typing plead in favor of this transmission (Rabodonirina et al, 2004;Hocker et al, 2005;de Boer et al, 2007). Moreover, investigations of subjects colonized with P. jirovecii, based on a genotyping approach, have suggested that these populations have a role in the circulation or transmission of the microorganism (Totet et al, 2004).…”

High Prevalence of Pneumocystis jirovecii Dihydropteroate Synthase Gene Mutations in Patients with a First Episode of Pneumocystis Pneumonia in Santiago, Chile, and Clinical Response to Trimethoprim-Sulfamethoxazole Therapy

“…DHPS mutant genotypes are selected by sulfa drug selection pressure and have been used as a marker to infer interhuman transmission of mutant Pneumocystis genotypes from sulfa drug-treated patients to individuals not treated with sulfonamides (14)(15)(16). The prevalence of these genotypes varies depending on geographical location, suggesting different patterns in the use of sulfa drugs.…”