Pneumocystis jirovecii pneumonia in intensive care units: a multicenter study by ESGCIP and EFISG.

BACKGROUND: Pneumocystis jirovecii pneumonia (PJP) is an opportunistic, life-threatening disease commonly affecting immunocompromised patients. The distribution of predisposing diseases or conditions in critically ill patients admitted to intensive care unit (ICU) and subjected to diagnostic work-up for PJP has seldom been explored. MATERIALS AND METHODS: The primary objective of the study was to describe the characteristics of ICU patients subjected to diagnostic workup for PJP. The secondary objectives were: (i) to assess demographic and clinical variables associated with PJP; (ii) to assess the performance of Pneumocystis PCR on respiratory specimens and serum BDG for the diagnosis of PJP; (iii) to describe 30-day and 90-day mortality in the study population. RESULTS: Overall, 600 patients were included in the study, of whom 115 had presumptive/proven PJP (19.2%). Only 8.8% of ICU patients subjected to diagnostic workup for PJP had HIV infection, whereas hematological malignancy, solid tumor, inflammatory diseases, and solid organ transplants were present in 23.2%, 16.2%, 15.5%, and 10.0% of tested patients, respectively. In multivariable analysis, AIDS (odds ratio [OR] 3.31; 95% confidence interval [CI] 1.13-9.64, p = 0.029), non-Hodgkin lymphoma (OR 3.71; 95% CI 1.23-11.18, p = 0.020), vasculitis (OR 5.95; 95% CI 1.07-33.22, p = 0.042), metastatic solid tumor (OR 4.31; 95% CI 1.76-10.53, p = 0.001), and bilateral ground glass on CT scan (OR 2.19; 95% CI 1.01-4.78, p = 0.048) were associated with PJP, whereas an inverse association was observed for increasing lymphocyte cell count (OR 0.64; 95% CI 0.42-1.00, p = 0.049). For the diagnosis of PJP, higher positive predictive value (PPV) was observed when both respiratory Pneumocystis PCR and serum BDG were positive compared to individual assay positivity (72% for the combination vs. 63% for PCR and 39% for BDG). Cumulative 30-day mortality and 90-day mortality in patients with presumptive/proven PJP were 52% and 67%, respectively. CONCLUSION: PJP in critically ill patients admitted to ICU is nowadays most encountered in non-HIV patients. Serum BDG when used in combination with respiratory Pneumocystis PCR could help improve the certainty of PJP diagnosis.

Population genomics confirms acquisition of drug-resistant Aspergillus fumigatus infection by humans from the environment.

Infections caused by the fungal pathogen Aspergillus fumigatus are increasingly resistant to first-line azole antifungal drugs. However, despite its clinical importance, little is known about how susceptible patients acquire infection from drug-resistant genotypes in the environment. Here, we present a population genomic analysis of 218 A. fumigatus isolates from across the UK and Ireland (comprising 153 clinical isolates from 143 patients and 65 environmental isolates). First, phylogenomic analysis shows strong genetic structuring into two clades (A and B) with little interclade recombination and the majority of environmental azole resistance found within clade A. Second, we show occurrences where azole-resistant isolates of near-identical genotypes were obtained from both environmental and clinical sources, indicating with high confidence the infection of patients with resistant isolates transmitted from the environment. Third, genome-wide scans identified selective sweeps across multiple regions indicating a polygenic basis to the trait in some genetic backgrounds. These signatures of positive selection are seen for loci containing the canonical genes encoding fungicide resistance in the ergosterol biosynthetic pathway, while other regions under selection have no defined function. Lastly, pan-genome analysis identified genes linked to azole resistance and previously unknown resistance mechanisms. Understanding the environmental drivers and genetic basis of evolving fungal drug resistance needs urgent attention, especially in light of increasing numbers of patients with severe viral respiratory tract infections who are susceptible to opportunistic fungal superinfections.

Evaluation of the BD MAX Enteric Parasite Panel for the detection of Cryptosporidium parvum/hominis, Giardia duodenalis and Entamoeba histolytica.

PURPOSE: Conventional laboratory detection methods for gastrointestinal parasites are time consuming, require considerable technical expertise and may suffer from poor analytical sensitivity. This study sought to evaluate the automated BD MAX Enteric Parasite Panel (EPP) for the detection of Cryptosporidium parvum/hominis, Entamoeba histolytica and Giardia duodenalis.Methodolgy. A total of 104 known positive samples (43 Cryptosporidium parvum/hominis and 61 G. duodenalis), 15 simulated samples (E. histolytica and other Entamoeba species) and 745 patient stool samples, submitted for enteric pathogen culture and microscopy, were inoculated into BD MAX EPP sample buffer tubes (SBTs). All specimens were blinded and tested within 7 days of SBT inoculation using the BD MAX EPP assay with results compared to those generated by microscopy.Results/Key findings. Combining the results from the known positive samples and anonymously tested patient samples, the sensitivity of the BD MAX EPP assay was 100 % for both Cryptosporidium spp. and G. duodenalis. Specificities of 99.7 and 98.9 % were calculated for the detection of Cryptosporidium spp. and G. duodenalis respectively. Insufficient clinical specimen data was available to determine the performance of the assay for E. histolytica detection. CONCLUSIONS: The findings of this study indicate that the BD MAX EPP is suitable for the detection of Cryptosporidium parvum/hominis and G. duodenalis from clinical specimens with reduced hands-on time and complexity compared to microscopy. Results for the detection of E. histolytica were promising although further work is required to evaluate the assay for the detection of this pathogen.

Aspergillus PCR - Platforms, strengths and weaknesses.

PCR is a useful tool to aid in the diagnosis of invasive aspergillosis. However, it is essential that an optimal method be agreed to allow inclusion in future consensus diagnosis criteria. It should be used in conjunction with other methods (e.g., galatomannan (GM) ELISA and high resolution computed tomography (HRCT)) to enhance the opportunity for detection of this devastating infection. This manuscript will try to highlight the benefits but mainly the limitations occurring throughout the process of molecular testing. It will focus on real-time methods although many of the points will be relevant to block-based amplification.