Nosocomial transmission of Pneumocystis carinii in renal transplantation

Multilocus Sequence Typing of Pneumocystis jirovecii from Clinical Samples: How Many and Which Loci Should Be Used?

“…In most instances, these cases were described in kidney transplant recipients, and interhuman transmission was confirmed in most reports by molecular typing (13). In France, to the best of our knowledge, at least eight distinct outbreaks have been reported since 1990 (11,(32)(33)(34)(35)(36)(37)(38). Epidemiological investigations of a putative nosocomial cluster of PCP usually rely on the study of patient encounters through a transmission map (11,(14)(15)(16), combined with the molecular typing of P. jirovecii performed directly on clinical samples, as this fungal pathogen cannot be cultured in vitro (1).…”

“…One of our important findings is the high performance of the eight-locus MLST scheme as demonstrated by the H-index value (H-index, 0.996). However, as this procedure can be time-consuming, a second aim of this project was to examine a reduced scheme displaying sufficient discriminatory power to be used for preliminary investigations of PCP outbreaks, as well as to examine the performance of several MLST schemes that were previously published by others (17,20,22,24,33). Unfortunately, the recently proposed MLST scheme relying on five loci (mt26S, ITS1, ITS2, ␤-TUB, and DHPS) could not be evaluated, as ITS2 was not included in our study (http://mlst.mycologylab.org).…”

“…Our data suggest that at least three to four loci are required for sufficient discrimination of P. jirovecii isolates. Indeed, some previously published schemes relying on one or two loci displayed insufficient performance (H-index, Ͻ0.95) and may lead to underestimating the genetic diversity of P. jirovecii, increasing the risk that the isolates will be identified, by default, as a clonal cluster (20,24,33). In our study, two MLST schemes appeared to provide suitable discriminatory power to be used for primary investigations of PCP outbreaks: the four-locus scheme first described by Hauser (ITS1, 26S, mt26S, and ␤-TUB) and the new scheme evaluated in the present study (SOD, mt26S, and CYB).…”

Prevention of Infection Caused byPneumocystis cariniiin Transplant Recipients

“…Relatively few organisms (10-100 cysts) are needed to cause infection in immunocompromised animals [42]. Epidemiologic studies and reports of clusters of infection in oncology centers and in renal transplant recipients support the acquisition of infection from environmental or human sources [43][44][45][46][47]. Molecular studies in animals and humans, using a variety of genetic probes, have suggested that both reinfection and reactivation of latent infection are significant factors in disease incidence [48,49].…”

Development and Characterization of a Molecular Viability Assay forPneumocystis cariniif sphominis

“…Evidence suggesting that P. carinii has an environmental reservoir includes the detection of P. carinii DNA in ambient air [2] and the high seroprevalence of P. carinii antibodies in young children [3]. However, the detection of human P. carinii DNA in homes and hospital rooms of patients with PCP [4] and epidemiologic studies of PCP outbreaks [5] suggest the possibility of person-to-person transmission. Person-to-person transmission is further supported by a recent report of transmission of P. carinii DNA from a patient with PCP to 2 immunocompetent health care workers [6] and the finding that the genotype associated with trimethoprimsulfamethoxazole (TMP-SMZ) resistance is geographically limited and occurs in persons not receiving prophylaxis [7].…”