Performance of the RealStar® Pneumocystis jirovecii PCR kit for the diagnosis of Pneumocystis pneumonia.

BACKGROUND: Pneumonia due to Pneumocystis jirovecii (PCP) is a frequent infection in HIV-positive and also in immunocompromised HIV-negative patients. PCR analysis of pulmonary samples has become an essential element in PCP laboratory diagnosis. Currently, many commercially PCR-based tests are available for P jirovecii detection and need to be evaluated. OBJECTIVES: We evaluated the performance of the RealStar® P jirovecii PCR kit for PCP diagnosis. METHODS: We performed the RealStar® P jirovecii PCR and an in-house PCR in 219 pulmonary samples. We then assessed the performance of the RealStar® P jirovecii PCR kit by classifying patients in proven, probable, possible PCP or no final diagnosis, on the basis of the clinical and radiological signs and direct examination of bronchoalveolar lavage samples. RESULTS: The results showed excellent concordance (96.8%) with another in-house PCR, previously used in the laboratory. The available clinical data allowed classifying 219 patients as having proven PCP (n = 6), probable PCP (n = 27), possible PCP (n = 29) and no final diagnosis of PCP (n = 157). The RealStar® P jirovecii PCR kit performed well with samples from patients with proven and probable PCP, as indicated by the detection of P jirovecii DNA in all these samples. The percentage of positive samples in the possible PCP category was 75.9%. In patients with no final diagnosis of PCP, P jirovecii DNA was detected in 13.4% of samples, indicating colonisation by this pathogen. CONCLUSIONS: The RealStar® P jirovecii PCR kit shows excellent performance for PCP diagnosis.

Successful Terbinafine Treatment for Cutaneous Phaeohyphomycosis Caused by Trematosphaeria grisea in a Heart Transplanted Man: Case Report and Literature Review.

Phaeohyphomycosis is a chronic infectious disease caused by dematiaceous fungi. It is characterized by the presence of pigmented septate mycelia within tissues. In the case of superficial infection, the lesion(s) chronically evolve(s) toward painless pseudo-tumor(s) of the soft parts. We report herein the original case of a heart transplanted man who exhibited phaeohyphomycosis of the left hand, with no mention of travels in endemic areas. Trematosphaeria grisea was identified as the causative agent, which is quite innovative since this species has been rather described in mycetoma. The antifungal treatment initially based on isavuconazole alone was not sufficient to cure the patient. In contrast, its association with local terbinafine ointment allowed total clinical improvement. This finding is unusual as diagnosis of phaeohyphomycosis caused by T. grisea is uncommon in nontropical countries, and as the outcome appeared successful by the means of add-on therapeutic strategy with terbinafine.

Combination of ß-(1, 3)-D-glucan testing in serum and qPCR in nasopharyngeal aspirate for facilitated diagnosis of Pneumocystis jirovecii pneumonia.

BACKGROUND: Currently, the biological diagnosis of Pneumocystis jirovecii pneumonia (PjP infection) usually relies on microbiological investigations in bronchial-alveolar lavage fluid (BALF) by conventional staining methods and/or molecular biology. However, bronchial-alveolar lavage is sometimes complicated to manage, especially in weakened patients. Therefore, alternative clinical samples-easier to collect-are warranted in such specific contexts. OBJECTIVE: Over a four-year period, diagnostic performance of an original method based on combination of quantitative real-time polymerase chain reaction (qPCR) in nasopharyngeal aspirate (NPA) with measurement of ß-(1, 3)-D-glucan antigen (BDG) in serum was prospectively assessed in a single centre. PATIENTS/METHODS: Results were compared with those obtained in BALF through direct staining methods and qPCR. True positives were defined by an independent committee based on clinical, radiological and biological data. Overall, 48 individuals with a definitive diagnosis of PjP infection were included, and 48 controls were selected upon matching for age, sex and underlying disease(s). RESULTS: qPCR results were strongly correlated between BALF and NPA (P < .0001). Altogether, greater diagnostic performance was achieved when establishing the positive cut-off of BDG antigen at 143 pg/mL. In such conditions, sensitivity of the testing based on either positive BDG measurement or positive qPCR in NPA was then calculated at 93.75%, 95% CI [82.37%-98.40%], and specificity at 97.87%, 95% CI [87.66%-100.00%]. CONCLUSIONS: Further validation through multicentre studies is now required, especially for establishing clear cut-offs. However, one could already state that combination of qPCR in the NPA with BDG measurement in serum may be a valuable substitute for BALF examination.

BD BACTEC™ Mycosis IC/F culture vials for fungemia diagnosis and follow-up: a retrospective study from 2013 to 2020.

This retrospective study compared the BD BACTEC™ Mycosis IC/F with the BD BACTEC™ Plus Aerobic/F and BD BACTEC™ Lytic Anaerobic/F culture vials (i.e., standard vials) for fungemia diagnosis at Nîmes University Hospital, France. From 2013 to 2020, 57 blood samples were concomitantly collected in the 3 culture vial types. For 43.8% of these samples, all vials were positive for yeast. The mean time to positivity was shorter (32.0 hours vs 44.2 hours; -12.2 hours) and longer (89.4 hours vs 33.7 hours; +55.7 hours) with the BD BACTEC™ Mycosis IC/F culture vials than with the other culture vials in patients without and with antifungal treatment, respectively. Moreover 31.6% and 24.6% of samples were positive only with the standard vials and with the BD BACTEC™ Mycosis IC/F culture vials, respectively. The BD BACTEC™ Mycosis IC/F culture vials are useful for the initial fungemia diagnosis (before any treatment) because they provide faster results.

Gradient concentration strip-specific epidemiological cut-off values of antifungal drugs in various yeast species and five prevalent Aspergillus species complexes.

OBJECTIVES: To determine the epidemiological cut-off values (ECVs) of ten antifungal agents in a wide range of yeasts and Aspergillus spp. using gradient concentration strips. METHODS: The minimum inhibitory concentrations for amphotericin B, anidulafungin, caspofungin, micafungin, flucytosine, fluconazole, itraconazole, isavuconazole, posaconazole, and voriconazole, determined with gradient concentration strips at 35 French microbiology laboratories between 2002 and 2020, were retrospectively collected. Then, the ECVs were calculated using the iterative method and a cut-off value of 97.5%. RESULTS: Minimum inhibitory concentrations were available for 17 653 clinical isolates. In total, 48 ECVs (including 32 new ECVs) were determined: 29 ECVs for frequent yeast species (e.g. Candida albicans and itraconazole/flucytosine, and Candida glabrata species complex [SC] and flucytosine) and rare yeast species (e.g. Candida dubliniensis, Candida inconspicua, Saccharomyces cerevisiae, and Cryptococcus neoformans) and 19 ECVs for Aspergillusflavus SC, Aspergillusfumigatus SC, Aspergillusnidulans SC, Aspergillusniger SC, and Aspergillusterreus SC. CONCLUSIONS: These ECVs can be added to the already available gradient concentration strip-specific ECVs to facilitate minimum inhibitory concentration interpretation and streamline the identification of nonwild type isolates.

Kazachstania slooffiae: An unexpected journey to a human pleural sample.

We report a case of a 50-year-old shepherd hospitalized in intensive care unit for hiatal hernia complicated by an occlusive syndrome. In post-surgery, an acute respiratory distress occurs due to mediastinitis with large pleural effusion. At the laboratory, direct examination of the pleural sample revealed the presence of pseudohyphae. Kazachstania slooffiae was identified by Mass Spectrometry and confirmed by DNA sequencing. This uncommon yeast has never been previously described in human infections. Although its pathogenicity is not well known, K. slooffiae should be considered in the case of critically ill patients.

Some undesirable traps which can mislead the pathologist.

In clinical laboratories, the diagnosis of parasite diseases can sometimes be challenging for non-expert microbiologists. Indeed, in spite of the advent of the molecular biology, macroscopic and microscopic examinations still remain essential. Nonetheless, it is usually not automated and requires great skills to complete the correct diagnosis. It is not infrequent that inert elements mislead to erroneous diagnoses. Through three different concrete examples, this article aims at underscoring the actual risk of parasite misidentification and at highlighting the systematic approach to be conducted in order to enable reliable diagnosis.

[Tricks and misuses of rapid diagnostic testing for malaria diagnosis]. / Pièges et mésusages des tests de diagnostic rapide pour rechercher le paludisme en routine.

Molecular biology or immunochromatographic tests are conventionally offered as aids in the routine diagnosis of malaria. However, the interpretation of their results requires a precise knowledge of their limits, both by the biologist and the physician. It is in particular conditioned by thorough interview of the patient in order to seek a history of recent or even older malaria disease. We discuss herein the different usages and how to interpret such diagnostics, through a concrete example of a malaria case which was particularly tough to investigate.