Conventional polymerase chain reaction (PCR) in respiratory samples does not differentiate between Pneumocystis pneumonia (PCP) and Pneumocystis jirovecii (Pj) colonization. We used Pj real-time quantitative PCR (qPCR) with the objective to discriminate PCP from Pj colonization in immunocompromised patients. All positive Pj qPCR [targeting the major surface glycoprotein (MSG) gene] obtained in respiratory samples from immunocompromised patients presenting pneumonia at the Grenoble University Hospital, France, were collected between August 2009 and April 2011. Diagnoses were retrospectively determined by a multidisciplinary group of experts blinded to the Pj qPCR results. Thirty-one bronchoalveolar lavages and four broncho aspirations positive for the Pj qPCR were obtained from 35 immunocompromised patients. Diagnoses of definite, probable, and possible PCP, and pneumonia from another etiology were retrospectively made for 7, 4, 5, and 19 patients, respectively. Copy numbers were significantly higher in the "definite group" (median 465,000 copies/ml) than in the "probable group" (median 38,600 copies/ml), the "possible group" (median 1,032 copies/ml), and the "other diagnosis group" (median 390 copies/ml). With the value of 3,160 copies/ml, the sensitivity and specificity of qPCR for the diagnosis of PCP were 100 % and 70 %, respectively. With the value of 31,600 copies/ml, the sensitivity and specificity were 80 % and 100 %, respectively. The positive predictive value was 100 % for results with more than 31,600 copies/ml and the negative predictive value was 100 % for results with fewer than 3,160 copies/ml. qPCR targeting the MSG gene can be helpful to discriminate PCP from Pj colonization in immunocompromised patients, using two cut-off values, with a gray zone between them.

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In infective endocarditis (IE), brain magnetic resonance imaging (MRI) is helpful to diagnose clinically silent neurological events. We assessed the usefulness of systematic early brain MRI in IE diagnosis and medico-surgical management. Over a period of 1 year, all patients admitted in one of the three hospitals participating in and fulfilling the Duke criteria for definite or possible IE underwent cerebral MRI within 7 days of IE suspicion. Eight panels of experts analyzed the records a posteriori. For each case, one record with and one record without the MRI results were randomly assigned to two panels, which determined the theoretical diagnosis and treatment. Paired comparisons were performed using a symmetry test. Thirty-seven brain MRIs were performed within a median of 5 days after inclusion. MRI was pathological in 26 patients (70 %), showing 62 % microischemia and 58 % microbleeds. The expert advice did not differ significantly between the two evaluations (with or without the MRI results). The therapeutic strategies determined diverged in five cases (13.5 %). Diagnosis differed in two cases (5.4 %), with an upgrading of diagnosis from possible to definite IE using MRI results. Early brain MRI did not significantly affect the IE diagnosis and medico-surgical treatment plan. These results suggest that systematic use of early brain MRI is irrelevant in IE. Further studies are necessary to define whether MRI is mandatory in IE management within a multidisciplinary approach, with particular attention paid to better timing and the subset of patients in whom this imaging examination could be beneficial.

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