Pneumocystis colonisation is common among hospitalised HIV infected patients with non-Pneumocystis pneumonia

Abstract

Results: 68% (117/172) of all patients were colonised with Pneumocystis. No strong associations with colonisation were identified for any demographic factors. Among clinical factors, having a CD4+ T cell count (50 cells/ml (unadjusted OR 2.4, 95% CI 1.09 to 5.48; p = 0.031) and using PCP prophylaxis (unadjusted OR 0.55, 95% CI 0.29 to 1.07; p = 0.077) were associated with Pneumocystis colonisation, although the latter association may have been due to chance. After adjustment for CD4+ T cell count, use of PCP prophylaxis was associated with a decreased odds of colonisation (adjusted OR 0.45, 95% CI 0.21 to 0.98; p = 0.045). 11 patients who were colonised were subsequently readmitted for evaluation of a second episode of pneumonia; three were found to be colonised again, but none had PCP. Conclusions: The majority of hospitalised HIV infected patients with non-PCP pneumonia are colonised with Pneumocystis. Failure to use co-trimoxazole prophylaxis and severe immunosuppression are associated with an increase in the odds of colonisation. Pneumocystis colonisation among hospitalised patients does not commonly lead to PCP.

Impact of HIV Infection Status on Interpretation of Quantitative PCR for Detection of Pneumocystis jirovecii

“…Some authors support the initiation of a specific therapy when immunosuppression is persistent, considering that colonization could represent an early stage of the disease (27,28). However, this risk was found to be low in HIVinfected patients (29) and has only occasionally been reported in other immunocompromised patients (28,30,31). In our study, there was one case of an HIV-positive patient, diagnosed as colonized based on a first BAL fluid analysis, who was not treated with anti-Pneumocystis therapy, and whose second BAL fluid sample, 10 days later, was negative for P. jirovecii by qPCR.…”

Multicenter, Prospective Clinical Evaluation of Respiratory Samples from Subjects at Risk for Pneumocystis jirovecii Infection by Use of a Commercial Real-Time PCR Assay

“…In this study, 1 of the 9 (11%) patients who were PCR positive and PCP negative at study exit developed PCP within 6 weeks of the initial diagnosis despite normal chest X-ray and CT results and negative microscopy results at the time of the study. The remaining 8 patients, for whom details are given in Table 4, did not progress to PCP infection during the 3 months of follow-up, and it is likely that the P. jirovecii amplified from the clinical samples of these patients is the result of colonization (6,12,19,25,37). Since microscopy and immunofluorescence are part of the diagnostic algorithm, a negative test is diagnostic for the absence of infection but may also be due to sampling error, low fungal burdens, or few P. jirovecii cysts.…”

Granulomatous Pneumocystis Jiroveci Pneumonia Associated With Immune Reconstituted Hiv

“…PCP colonization is seen in 20% of healthy adults (10), 44% of non-HIV immunocompromised individuals and 46% of HIV-infected hosts without active PCP (11). Risk factors for PCP colonization include HIV infection, corticosteroid use and chronic lung disease (9). It is unclear whether PCP colonization represents the presence of active organisms and, as such, predisposes patients to subsequent PCP infection.…”

“…Colonization is detected with polymerase chain reaction assays targeting the large subunit of mitochondrial ribosomal RNA (9). PCP colonization is seen in 20% of healthy adults (10), 44% of non-HIV immunocompromised individuals and 46% of HIV-infected hosts without active PCP (11).…”