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1.
Klin Onkol ; 33(2): 138-144, 2020.
Article in English | MEDLINE | ID: mdl-32303134

ABSTRACT

BACKGROUND: Invasive fungal infections are a life-threatening complication of cancer treatments, especially in hemato-oncological patients. Mucormycosis is the third leading cause of invasive fungal infections after Aspergillus and Candida infections. The first clinical symptoms are usually non-specific, which can lead to a late diagnosis and delayed therapy. PURPOSE: The objective of this report is to summarize data in the literature about mucormycosis and to present a case report of a patient with acute lymphoblastic leukemia, who developed this infection at our center. Risk factors for the development of mucormycosis, clinical symptoms, radiology, laboratory results, and outcome were retrospectively evaluated. CASE: We describe a 6-years-old female patient with acute lymphoblastic leukemia. During the induction phase of therapy, the patient developed febrile neutropenia and did not respond to therapy with a combination of antibiotics and supportive treatment. Pansinusitis and orbitocellulitis developed. Examination of the biological material revealed that the etiological agent was a Rhizopus sp. The patient was treated with a combination of antimycotic drugs, but the infection disseminated to the central nervous system. She underwent radical surgical resection of the affected tissue. At this time, she is still under treatment with antimycotic and oncology agents, but is in remission of the main diagnosis and in good clinical condition. CONCLUSION: Mucormycosis is an invasive fungal infection with high morbidity and mortality. Early diagnosis and initiation of effective therapy using a combination of amphotericin B administration and surgery are necessary to obtain a favorable outcome. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.


Subject(s)
Amphotericin B/therapeutic use , Antifungal Agents/therapeutic use , Antineoplastic Agents/therapeutic use , Mucormycosis , Orbital Cellulitis , Precursor Cell Lymphoblastic Leukemia-Lymphoma/drug therapy , Rhizopus , Sinusitis , Central Nervous System/microbiology , Child , Female , Humans , Mucormycosis/drug therapy , Mucormycosis/etiology , Mucormycosis/microbiology , Mucormycosis/surgery , Orbital Cellulitis/drug therapy , Orbital Cellulitis/etiology , Orbital Cellulitis/microbiology , Orbital Cellulitis/surgery , Precursor Cell Lymphoblastic Leukemia-Lymphoma/microbiology , Precursor Cell Lymphoblastic Leukemia-Lymphoma/surgery , Sinusitis/drug therapy , Sinusitis/etiology , Sinusitis/microbiology , Sinusitis/surgery
2.
Vnitr Lek ; 62(4): 287-98, 2016 Apr.
Article in Czech | MEDLINE | ID: mdl-27250606

ABSTRACT

Castlemans disease is the term for reactive lymphocytary and plasmocytary proliferation which occurs in the unicentric (localized) form, usually without systemic symptoms, or in the generalized/multicentric form, typically with systemic symptoms (www.vzacne-diagnozy.cz). Over the past 25 years we diagnosed, treated and followed 14 histologically proven cases of Castlemans diseases. Seven patients had the localised form of the disease. In 5 of 7 cases the pathological lesion was located intrathoracically or intraabdominally and in only 2 cases it was on the surface of the body. No clinical symptoms were present in any of the patients with the unicentric form of the disease and surgical treatment led to the total removing of the disease in all of them. As opposed to that, all 7 patients with the multicentric form of Castlemans disease experienced febrile or subfebrile temperatures. Three of the 7 patients complained of severe troubling night sweats. Clinical expressions of vasculitis which was the cause of stroke, were present in 1 of 7 patients. Osteosclerotic changes on the skeleton were detected in 1 patient, who also suffered from fluid retention likely associated with this disease. Polyclonal propagation of immunoglobulins, predominantly immunoglobulin IgG type, was present in 5 of 7 patients with the multicentric form. In one case there was one complete molecule of monoclonal imunoglobuline present and in one case loose light chains κ were increased More than 1 sampling of material for histological examination of enlarged lymph nodes were needed in 6 of 7 patients for diagnosing the multicentric form of the disease. It has turned out beneficial with respect to diagnosing the disease to carry out surgical removal and histological examination of the nodes which accumulated the most fluorodeoxyglucose within PET-CT examination. The text describes experience of the treatment. In recent years the basis for the treatment has been the monoclonal antibody antiCD20 rituximab, or thalidomide and lenalidomide, or possibly their combination. The new medicine for these patients is interleukin-6 antibody called siltuximab (Sylvant), of which we have no own experience so far. Five of our seven patients with the multicentric form received treatment, 1 patient refused treatment and in one patient the signs of the disease activity are not expressed to such extent that would require treatment. The therapy containing rituximab reached complete remission in 2 patients and the therapy containing thalidomide and lenalidomide achieved the complete remission of the disease in 3 patients. In one of the above described cases the disease did not respond to the initial treatment with rituximab and remission was reached by thalidomide and lenalidomide and in one case the disease did not respond to the initial treatment with thalidomide and complete remission was reached with rituximab. Following the treatment, no patient with the multicentric form of Castlemans disease has had a relapse until now.


Subject(s)
Castleman Disease/drug therapy , Aged , Angiogenesis Inhibitors/therapeutic use , Antibodies, Monoclonal/therapeutic use , Drug Therapy, Combination , Follow-Up Studies , Humans , Lenalidomide , Male , Middle Aged , Remission Induction , Rituximab/therapeutic use , Thalidomide/analogs & derivatives , Thalidomide/therapeutic use
3.
Med Mycol ; 54(7): 714-24, 2016 Oct 01.
Article in English | MEDLINE | ID: mdl-27161789

ABSTRACT

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.


Subject(s)
Bronchoalveolar Lavage Fluid/microbiology , DNA, Fungal/genetics , Fungi/isolation & purification , Lung Diseases, Fungal/diagnosis , Molecular Diagnostic Techniques/methods , Polymerase Chain Reaction/methods , Transition Temperature , DNA, Fungal/chemistry , DNA, Ribosomal Spacer/chemistry , DNA, Ribosomal Spacer/genetics , Female , Fungi/classification , Fungi/genetics , Humans , Lung Diseases, Fungal/microbiology , Male , Predictive Value of Tests , Sensitivity and Specificity , Time Factors
4.
Mycoses ; 59(1): 48-55, 2016 Jan.
Article in English | MEDLINE | ID: mdl-26661324

ABSTRACT

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.


Subject(s)
Anemia, Aplastic/complications , Antifungal Agents/therapeutic use , Fusariosis/diagnosis , Immunocompromised Host , Opportunistic Infections/diagnosis , Triazoles/therapeutic use , Antifungal Agents/pharmacology , Aspergillosis/complications , Aspergillosis/microbiology , Aspergillus flavus/drug effects , Aspergillus flavus/isolation & purification , Coinfection , Fatal Outcome , Fusariosis/complications , Fusariosis/drug therapy , Fusariosis/microbiology , Fusarium/drug effects , Fusarium/isolation & purification , Humans , Male , Opportunistic Infections/drug therapy , Opportunistic Infections/microbiology , Young Adult
5.
Vnitr Lek ; 61(3): 251-9, 2015 Mar.
Article in Czech | MEDLINE | ID: mdl-25873122

ABSTRACT

We describe a case of multicentric Castleman disease with generalized lymphadenopathy and splenomegaly, accompanied by typical B symptoms - loss of 15 kg, fever of non-infectious origin, night sweats, symptoms of anemia. Histological examination of the nodes with the highest accumulation of fluorodeoxyglucose, taken from mediastinum by thoracoscopy, revealed plasmocellular type of Castleman disease. Tests for HIV and human herpesvirus 8 (HHV-8) were negative. Three recurrences of herpes zoster indicating an alteration of immunity preceded the dia-gnosis of disease. Treatment was initiated with combination of thalidomide, dexamethasone, and cyclophosphamide. The response after 2 months therapy was not clear and patient doesn't tolerated the therapy well. Therefore, this treatment was terminated and R-CHOP (Mabthera - rituximab, cyclophosphamide, adriamycin, vincristine, and prednisone) was selected as a second-line therapy. Lymphadenopathy and splenomegaly were reduced during the 2 cycles of treatment, however, serious infectious complications accompanied the therapy. Therefore, only use of Mabthera monotherapy 375 mg /m2 was administered in 28-day intervals. This treatment has shown efficacy and tolerability. PET-CT scan has demonstrated disappearance of lymphadenopathy and splenomegaly, in addition, normalized accumulation of fluorodeoxyglucose. Monotherapy with Mabthera has proved to be effective and well tolerated drug in this case. Currently, there are more effective therapeutic alternatives in multicentric Castleman disease: treatment with monotherapy of rituximab or in combination therapy with immunomodulatory drugs (thalidomide or lenalidomide, treatment with anti-IL-6 (siltuximab) or against its receptor (tocilizumab). In the case of ineffectiveness of one treatment option must be tested other alternative. In this case the therapy based on thalidomide wasn't successful, whereas the treatment with Mabthera has achieved disappearance of disease symptoms.


Subject(s)
Antibodies, Monoclonal, Murine-Derived/therapeutic use , Castleman Disease/diagnosis , Castleman Disease/drug therapy , Immunologic Factors/therapeutic use , Positron-Emission Tomography , Tomography, X-Ray Computed , Drug Therapy, Combination , Humans , Multimodal Imaging , Rituximab
6.
Am J Hematol ; 90(5): 417-21, 2015 May.
Article in English | MEDLINE | ID: mdl-25645263

ABSTRACT

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).


Subject(s)
Antibodies, Monoclonal/therapeutic use , Antineoplastic Agents/therapeutic use , Dexamethasone/therapeutic use , Leukemia, Lymphocytic, Chronic, B-Cell/drug therapy , Aged , Antibodies, Monoclonal, Humanized , Drug Administration Schedule , Drug Therapy, Combination/methods , Female , Humans , Leukemia, Lymphocytic, Chronic, B-Cell/genetics , Leukemia, Lymphocytic, Chronic, B-Cell/mortality , Leukemia, Lymphocytic, Chronic, B-Cell/pathology , Male , Middle Aged , Mutation , Recurrence , Survival Analysis , Tumor Suppressor Protein p53/genetics
7.
J Clin Virol ; 61(2): 270-4, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25130511

ABSTRACT

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.


Subject(s)
Cytomegalovirus/drug effects , Cytomegalovirus/genetics , Drug Resistance, Viral , Molecular Diagnostic Techniques/methods , Mutation, Missense , Real-Time Polymerase Chain Reaction/methods , Adult , Antiviral Agents/therapeutic use , Cytomegalovirus/isolation & purification , Cytomegalovirus Infections/drug therapy , Cytomegalovirus Infections/virology , Female , Hematopoietic Stem Cell Transplantation/adverse effects , Humans , Male , Middle Aged , Polymorphism, Restriction Fragment Length , Sequence Analysis, DNA , Transplantation, Homologous/adverse effects , Treatment Failure
8.
J Clin Microbiol ; 52(8): 2824-8, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24850354

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.


Subject(s)
Bronchoalveolar Lavage Fluid/microbiology , Lung Diseases, Fungal/diagnosis , Molecular Diagnostic Techniques/methods , Mucorales/classification , Mucorales/isolation & purification , Mucormycosis/diagnosis , Polymerase Chain Reaction/methods , Female , Humans , Immunocompromised Host , Lung Diseases, Fungal/microbiology , Male , Mucormycosis/microbiology , Predictive Value of Tests , Sensitivity and Specificity , Time Factors , Transition Temperature
9.
Klin Mikrobiol Infekc Lek ; 18(4): 96-101, 2012 Aug.
Article in Czech | MEDLINE | ID: mdl-23172020

ABSTRACT

Invasive fungal diseases (IFD) are a life-threatening infectious complications in immunocompromised patients and are associated with high rate of morbidity and mortality. The most common invasive mycosis in patients who underwent an allogeneic hematopoietic stem cell transplantation is invasive aspergilosis (IA), most frequently caused by the clinically dominant species Aspergillus fumigatus and, rarely, also by Aspergillus flavus, Aspergillus terreus and Aspergillus niger. In recent years, other related Aspergillus species were also reported to cause IFD, phenotypically similar to A. fumigatus and moreover, frequently exhibiting resistance towards various antifungals. For example, it is Aspergillus lentulus, Aspergillus viridinutans, Neosartoya fischeri, etc. Classical microbiological methods such as direct microscopy or culture are usually used for the identification of Aspergillus species. The application of PCR-based molecular techniques and monitoring of secondary metabolites production enable detection and identification of species, which are not distinguishable solely by their morphology. PCR methods are also useful for molecular strain typing of aspergilli and can reveal the genetic diversity of isolates.


Subject(s)
Aspergillosis/diagnosis , Immunocompromised Host , Aspergillosis/microbiology , Aspergillus/classification , Humans
10.
Klin Mikrobiol Infekc Lek ; 18(4): 109-14, 2012 Aug.
Article in Czech | MEDLINE | ID: mdl-23172022

ABSTRACT

Methods of molecular genetics offer rapid and sensitive detection and identification of fungal pathogens. The currently used methods are based mainly on PCR. With regard to the ubiquitous presence of fungi, it is important to prevent contamination during the whole process, from sampling to laboratory analyses. Molecular genetic methods are not included among the EORTC/MSG criteria used for the diagnosis of invasive fungal diseases since interlaboratory standardization is still missing. Another reason is the use of different target genes for PCR. ITS sequences from rDNA clusters are recommended for DNA barcoding of fungi. The use of DNA sequencing for identification of fungi in clinical samples has certain limitations and interpretation of results could be problematic in some cases. DNA sequences are searched and compared in public databases on the Internet, the best known of them being the GenBank. However, more reliable data for identification of fungi are offered by specialized mycological databases.


Subject(s)
Fungi/genetics , Molecular Diagnostic Techniques , Mycoses/diagnosis , DNA, Fungal/genetics , Fungi/classification , Humans , Molecular Biology , Mycoses/microbiology , Polymerase Chain Reaction , Sequence Analysis, DNA
11.
Int J Infect Dis ; 15(12): e874-81, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22040924

ABSTRACT

BACKGROUND: We evaluated the performance of a galactomannan (GM) assay in bronchoalveolar lavage (BAL) fluid compared to serum samples for the diagnosis of invasive pulmonary aspergillosis (IPA) in patients with hematological diseases. METHODS: Two hundred and fifty-five bronchoscopies were performed on 230 patients. Bronchial and alveolar samples from BAL fluid as well as serum samples were analyzed in the GM assay. RESULTS: Twenty-eight cases of IPA (11%) were diagnosed. The sensitivity, specificity, positive predictive value, and negative predictive value of the GM assay using a cut-off of 0.5 were 57.1%, 99.3%, 94.1%, and 92.5%, respectively, for the alveolar sample; 44.0%, 99.3%, 91.7%, and 91.4%, respectively, for the bronchial sample; and 60.7%, 100%, 100%, and 92.9%, respectively, for serum. The highest sensitivity (78.6%) with good specificity (98.6%) was obtained with a 'triple detection' of GM in bronchial, alveolar, and serum samples. Neutropenia and antifungal therapy for only 24h increased the sensitivity, while antifungal treatment for ≥ 2 days decreased assay performance. Moreover, a trend towards a higher volume of aspirated fluid in GM-negative BAL (p=0.092) was observed. CONCLUSIONS: In contrast to recently published data, we found only moderate sensitivity, but high specificity and high positive predictive value of the detection of GM in BAL fluid. In addition, neutropenia, antifungal therapy, and BAL standardization affected GM assay performance.


Subject(s)
Bronchoalveolar Lavage Fluid/chemistry , Hematologic Diseases/complications , Invasive Pulmonary Aspergillosis/diagnosis , Mannans/analysis , Adolescent , Adult , Aged , Antifungal Agents/adverse effects , Antifungal Agents/therapeutic use , Aspergillus/chemistry , Aspergillus/isolation & purification , Bronchoscopy , Cohort Studies , Female , Galactose/analogs & derivatives , Hematologic Neoplasms/complications , Humans , Invasive Pulmonary Aspergillosis/drug therapy , Invasive Pulmonary Aspergillosis/microbiology , Male , Mannans/blood , Middle Aged , Neutropenia/complications , Predictive Value of Tests , Retrospective Studies , Sensitivity and Specificity , Young Adult
12.
Klin Mikrobiol Infekc Lek ; 17(6): 194-200, 2011 Dec.
Article in Czech | MEDLINE | ID: mdl-22247029

ABSTRACT

Herpes virus infections represent common complications associated with respiratory tract involvement which may result in pneumonia development in immunocompromised patients. The analysis of bronchoalveolar lavage (BAL) fluid obtained from the lower respiratory tract may contribute to detection of aetiological agents of the disease. The routine use of quantitative molecular methods enables the discrimination between acute infection and viral reactivation with asymptomatic virus shedding. The aim of this review is to evaluate the contribution of BAL viral load monitoring in high-risk patients and to determine the cut-off of viral load leading to progression to herpes virus pneumonia.


Subject(s)
Bronchoalveolar Lavage Fluid/virology , Herpesviridae/isolation & purification , Immunocompromised Host , Pneumonia, Viral/diagnosis , Polymerase Chain Reaction , Humans , Pneumonia, Viral/immunology , Viral Load
13.
J Clin Microbiol ; 48(9): 3392-4, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20592150

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.


Subject(s)
DNA, Fungal/genetics , Mucorales/classification , Mucorales/isolation & purification , Mucormycosis/diagnosis , Mycology/methods , Polymerase Chain Reaction/methods , DNA, Fungal/chemistry , Humans , Molecular Sequence Data , Mucorales/genetics , Sequence Analysis, DNA , Transition Temperature
14.
Klin Mikrobiol Infekc Lek ; 13(5): 184-9, 2007 Oct.
Article in Czech | MEDLINE | ID: mdl-17987567

ABSTRACT

PCR detection of fungal pathogens in clinical samples has been discussed in journals for more than two decades. However, its use for diagnosing invasive aspergillosis is still controversial, despite the fact that molecular methods are routinely used in various fields of modern microbiology. These are e. g. genotyping of bacterial strains resistant to antibiotics, molecular epidemiology or routine detection of viral infections in clinical material. PCR methods have made the diagnostic applications faster, simpler and more accurate. This review deals with issues related to molecular methods for diagnosing invasive fungal infections and the main factors limiting their use in everyday clinical practice.


Subject(s)
Aspergillosis/diagnosis , Aspergillus/isolation & purification , DNA, Fungal/analysis , Polymerase Chain Reaction , Humans , Sensitivity and Specificity
15.
J Clin Microbiol ; 45(3): 1042-4, 2007 Mar.
Article in English | MEDLINE | ID: mdl-17229861

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.


Subject(s)
Base Sequence , Cytomegalovirus/genetics , Exons/genetics , Genes, Immediate-Early , Genetic Variation , Polymerase Chain Reaction/standards , DNA Primers , DNA, Viral/analysis , DNA, Viral/genetics , False Negative Reactions , Humans , Molecular Sequence Data , Polymerase Chain Reaction/methods , Sensitivity and Specificity , Sequence Analysis, DNA
16.
Klin Mikrobiol Infekc Lek ; 11(6): 204-9, 2005 Dec.
Article in Czech, English | MEDLINE | ID: mdl-16382414

ABSTRACT

AIM OF THE STUDY: The main goal was to explain the discrepancies between two PCR methods used for detection of cytomegalovirus (CMV) in peripheral blood samples of patients of Department of Internal Medicine-Hematooncology, University Hospital, Brno. MATERIALS AND METHODS: In past we used exon 4 of major immediate-early (MIE) gene as the target for quantitative detection of the CMV in clinical samples, but sometimes this method failed to detect the viral load in samples that were positively tested using less sensitive qualitative method targeting another region (exon 2-4) of the same gene. From January 2004 to January 2005 we totally tested samples from 363 patients. 64 patients were at least once CMV positive using quantitative method, but 20 patients were repeatedly false negative.To find the cause of this discrepancy we performed partial sequence analysis of this region (nt positions 2719-2919, GenBank M21295) and glycoprotein B (gB) genotyping. We sequenced samples from 35 patients-15 giving true positive (both in qualitative and quantitative method) and 20 giving false negative (negative in quantitative but positive in qualitative method) results in several consecutive blood samples. RESULTS: The 15 true positive samples were 100% homological, whereas all 20 false negative samples showed high degree of variation from the laboratory strain AD169. These changes are not random and indicate that the two groups of patients were infected by different CMV genotypes. Moreover, sequence alignment showed similarity to laboratory strains Toledo and Towne. No preferential concordance was observed between clinical context, MIE exon 4 sequence and gB groups. CONCLUSIONS: Because of high sequence variability exon 4 of MIE gene can not be used for routine diagnostics. Genetic varibility among the pathogenic strains may seriously affect its proper diagnostics.


Subject(s)
Cytomegalovirus Infections , Cytomegalovirus , Cytomegalovirus Infections/virology , DNA, Viral , Genotype , Humans , Polymerase Chain Reaction , Real-Time Polymerase Chain Reaction , Sensitivity and Specificity , Viral Load
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