Primary Study Of Molecular Epidemiology Of Pneumocystis In Immunocompromised Patients Without HIV Infection In Chongqing

Objective: To investigate the infecton rate of Pneumocystis carinii(PC) in immunocompromised patients without Human immunodeficiencyvirus (HIV) infection. To evaluate the diagnostic value of the Real-timefluorescence quantitative polymerse chain reaction (r-PCR) forHIV-negative immuonocompromised patients with Pneumocystispneumonia through comparing the efficiency of different testing methods.To conduct a preliminary analysis of gene polymorphism of PC’s internaltranscribed spacer (ITS) gene in Chongqing.Methods: Sputum specimens were collected from seventy-oneHIV-negative immunocompromised patients in Chongqing, including23connective tissue disease patients,21tumor patients after radiotherapy orchemotherapy,15blood disease patients,7liver transplantation patientsand5kidney transplantation patients. All the specimens were detected byGomori’s methenamine silver stained (GMS), ITS-nested PCR and r-PCR,respectively. The PCR products from both nested-PCR positive and r-PCRpositive samples were sequenced. The sequences were analyzed, aligned and compared with the sequences of PC from GenBank by BLAST program andDNAMAN software.Resμlts:(1)In the71sputum specimens, only2specimens werepositive thought GMS staining,25specimens were detected the PC by PCR,the infection rate of PC was35.21%, the infection rate of patients withcancer, heamatolagic disorder, kidney transplantation, liver transplantationand connective tissue disease were33.33%,26.67%,40.00%,42.86%,39.13%respectively. There was no significant difference between each casegroup of the infection rate. The infection rate was significantly higher thanthe reported abroad and as same as reported domestic in2009.(2)25sampleswere positive for nested-PCR, but the false-positive rate was high (36.00%).Sensitivity, specificity and positive predictive values (PPV) of nested-PCRwere88.89%,83.01%and64.00%, respectively. Using103copies/ml as acut-off value for the diagnosis of PCP, the sensitivity (83.33%) of r-PCR wasalmost equal to nested-PCR. Notably, its specificity and PPV were higherthan nested-PCR (98.11%and93.75%, respectively).(3)15sequences ofITS were obtained through the sequenced.11new ITS1sequences and4reported types (B,M,E,K) were identified.12new ITS2sequences wereobserved in addition to3types (g,i,b) reported previously.7new5.8SrRNAsequences were obtained.1previous combined type of ITS (Bi) and14newcombinations were observed. There were6-12nucleotide differences in allnew sequences compared with the prototype reported foreign, the main differences were base deletions and nucleotide substitutions.Conclusions: The infection rate of PC of HIV-negativeimmunocompromised patients in Chongqing is high, Clinician shoμldenhance the alertness of these patients with PCP. R-PCR on induced sputumis more usefμl for diagnosing PCP than neste-PCR in HIV-negativeimmunocompromized patients. Genetic diversity of PC is observed inChongqing and The PC from Chongqing may have the new genotyping.