Pavlína Volfová

Rapid Detection and Identification of Mucormycetes from Culture and Tissue Samples by Use of High-Resolution Melt Analysis

ABSTRACT We present a method for rapid and simple detection of clinically relevant mucormycetes of the Mucorales order in cultures and clinical samples. This seminested real-time PCR uses mucormycete-specific primers and is followed by species identification using high-resolution melt (HRM) analysis. The method is highly suitable for routine clinical diagnostics.

Rapid Detection and Identification of Mucormycetes in Bronchoalveolar Lavage Samples from Immunocompromised Patients with Pulmonary Infiltrates by Use of High-Resolution Melt Analysis

ABSTRACT Rapid differential diagnostics of pulmonary infiltrates suspected of invasive fungal disease in an immunocompromised host and early initiation of effective antifungal therapy are crucial for patient outcomes. There are no serological tests available to detect mucormycetes; therefore, PCR-based methods are highly suitable. We validated our previously published PCR followed by high-resolution melt analysis (PCR/HRMA) to detect Rhizopus spp., Rhizomucor pusillus, Lichtheimia corymbifera, and Mucor spp. in bronchoalveolar lavage (BAL) samples from immunocompromised patients who were at risk of invasive fungal disease. All PCR/HRMA-positive samples were retested using novel real-time quantitative PCR (RQ PCR) assays specific to the species identified. In total, between January 2009 and December 2012 we analyzed 99 BAL samples from 86 patients with pulmonary abnormalities using PCR/HRMA. Ninety (91%) BAL samples were negative, and 9 (9%) samples were positive. The sensitivity and specificity of PCR/HRMA were 100% and 93%, respectively. By combining the positive results of PCR/HRMA with positive RQ PCR results, the specificity was raised to 98%. PCR/HRMA, due to its high negative predictive value (99%), represents a fast and reliable tool for routine BAL sample screening for the differential diagnosis of pulmonary infiltrates in immunocompromised patients for the four most clinically important mucormycetes.

Ofatumumab added to dexamethasone in patients with relapsed or refractory chronic lymphocytic leukemia: Results from a phase II study

The treatment of relapsed/refractory chronic lymphocytic leukemia (CLL) remains a challenging clinical issue. An important treatment option is the use of high‐dose corticosteroids. The purpose of this clinical trial was to determine the efficacy and toxicity of an ofatumumab–dexamethasone (O‐Dex) combination in relapsed or refractory CLL. The trial was an open‐label, multicenter, nonrandomized, Phase II study. The O‐Dex regimen consisted of intravenous ofatumumab (Cycle 1: 300 mg on day 1, 2,000 mg on days 8, 15, and 22; Cycles 2–6: 1,000 mg on days 1, 8, 15, and 22) and oral dexamethasone (40 mg on days 1–4 and 15–18; Cycles 1–6). The O‐Dex regimen was given until best response, or a maximum of six cycles. Thirty‐three patients (pts) were recruited. Twenty‐four (73%) pts completed at least three cycles of therapy. The remaining nine pts were prematurely discontinued owing to Grade 3/4 infections (seven pts), disease progression (one pt), or uncontrollable diabetes mellitus (one pt). Overall response rates/complete remissions (ORR/CR) were achieved in 22/5 pts (67/15%). The median progression‐free survival (PFS) was 10 months. In pts with p53 defects (n = 8), ORR/CR were achieved in 5/2 pts (63/25%) with a median PFS of 10.5 months. The median overall survival (OS) was 34 months. The Grades 3–5 infectious toxicity in 33% of pts represented the most frequent side effect during the treatment period. In conclusion, the O‐Dex regimen shows a relatively high ORR and CR with promising findings for PFS and OS. The study was registered at www.clinicaltrials.gov (NCT01310101). Am. J. Hematol. 90:417–421, 2015.

Real-Time PCR Diagnostics Failure Caused by Nucleotide Variability within Exon 4 of the Human Cytomegalovirus Major Immediate-Early Gene

ABSTRACT Here we report how variability in the human cytomegalovirus genome sequence may seriously affect the outcome of its molecular diagnosis. A real-time quantitative PCR assay targeting the major immediate-early gene failed to detect the viral load in some, but not all, clinical samples from hematooncological patients. By amplification and sequencing the DNA across the regions targeted by this assay we found a number of nucleotide substitutions which accounted for decreased primer/probe binding. This decreased the sensitivity of the assay up to 1,000-fold.

Rapid detection of fungal pathogens in bronchoalveolar lavage samples using panfungal PCR combined with high resolution melting analysis.

Despite advances in the treatment of invasive fungal diseases (IFD), mortality rates remain high. Moreover, due to the expanding spectrum of causative agents, fast and accurate pathogen identification is necessary. We designed a panfungal polymerase chain reaction (PCR), which targets the highly variable ITS2 region of rDNA genes and uses high resolution melting analysis (HRM) for subsequent species identification. The sensitivity and specificity of this method was tested on a broad spectrum of the most clinically important fungal pathogens including Aspergillus spp., Candida spp. and mucormycetes. Despite the fact that fluid from bronchoalveolar lavage (BAL) is one of the most frequently tested materials there is a lack of literature sources aimed at panfungal PCR as an IFD diagnostic tool from BAL samples. The applicability of this method in routine practice was evaluated on 104 BAL samples from immunocompromised patients. Due to high ITS region variability, we obtained divergent melting peaks for different fungal species. Thirteen out of 18 patients with proven or probable IFD were positive. Therefore, the sensitivity, specificity, positive predictive value and negative predictive value of our method were 67%, 100%, 100%, and 94%, respectively. In our assay, fungal pathogens identification is based on HRM, therefore omitting the expensive and time consuming sequencing step. With the high specificity, positive and negative predictive values, short time needed to obtain a result, and low price, the presented assay is intended to be used as a quick screening method for patients at risk of IFD.

Disseminated fusariosis by Fusarium proliferatum in a patient with aplastic anaemia receiving primary posaconazole prophylaxis - case report and review of the literature.

Disseminated fusariosis is a life‐threatening, invasive, opportunistic infection in immunocompromised patients, especially those with haematological malignancies. The prognosis is poor because these fungi are resistant to many of the available antifungal agents. We present a case of disseminated fusariosis caused by Fusarium proliferatum in a patient with severe aplastic anaemia complicated by a secondary infection of Aspergillus flavus, with a fatal outcome. We also review the documented Fusarium infections in immunocompromised hosts.

Detecting human cytomegalovirus drug resistant mutations and monitoring the emergence of resistant strains using real-time PCR

BACKGROUND Antiviral resistance development is a serious complication of human cytomegalovirus virostatic therapy caused by mutations in UL 97 and/or UL54 genes. OBJECTIVES To determinate the presence of sensitive and resistant strains in patients developing antiviral resistance. STUDY DESIGN We used three different molecular biological methods for mutation analysis-restriction fragment length polymorphism, sequencing and real-time PCR approach. RESULTS We describe three allogeneic hematopoietic stem cell transplant patients developing the GCV resistant HCMV strains manifested by virostatic treatment failure. In these patients we identified UL97 mutations L595S, A594V and A594T and monitored the dynamics of coexisted sensitive/resistant strains. We confirmed the presence of mixed HCMV populations and in two patients a phenomenon of sensitive strain repopulation which occurred after 6.5 months and 1 month after removing GCV pressure. CONCLUSIONS Our results show changes in proportions of sensitive/resistant subpopulations over time but other studies would be required to demonstrate the beneficial impact of their monitoring on clinical outcome.

Monitoring of Epstein–Barr virus load in patients after allogeneic hematopoietic stem cell transplantation

Based on our results, we recommend the weekly monitoring of patients for at least 3 months after HSCT (2 out of 4 patients with EBV-associated disease passed the cut-off at week 11) and longer in patients with GVHD, due to the rapid progression of EBV infection, particularly in patients who develop clinical symptoms (lymphadenopathy, hepatosplenomegaly, or organ manifestations) related to EBV disease according to the European Conference on Infections in Leukemia (ECIL) 2011 guidelines. EBV reactivation occurred in some of the patients suffering fromGVHDin this cohort, but did not require clinical intervention unless the copy numbers were steadily increasing. A stable EBV viral load\1,000 copies/lg DNA temporarily occurred in some patients after HSCT; however, clinical symptoms of EBV infection did not develop and they did not require therapeutic intervention. Therefore, to improve the diagnostic value of EBV monitoring, the load measurement and quantitative monitoring of viral load kinetics is necessary.