Diagnosis Of Systemic Fungal Infections Research Articles

Performance of Blood culture, β -D-glucan and PCR for Diagnosis of Systemic Fungal Infection in Cancer Patients

Background and purpose: The incidence of systemic fungal infection has increased considerably in recent years. It is of greater concern because they are often misdiagnosed. The study aimed to assess the diagnostic performance of ELISA and Polymerase chain reaction versus the gold standard blood culture in diagnosing systemic fungal infection. Materials and Methods: The study included 70 cancer patients at the Mansoura University Oncology Center clinically suspected to suffer from systemic fungal infection. Blood samples were subjected to automated blood culture, antigen detection by ELISA and PCR for fungal DNA. Results: Considering the different methods used for diagnosis of systemic fungal infection, 19 patients were positive by blood culture, 36 patients were positive by ELISA and 32 patients were positive by PCR. Both β -D-glucan and PCR exhibited higher sensitivity, specificity and accuracy with higher NPV than PPV compared to the gold standard blood culture which lacks the desired sensitivity and specificity. Conclusion: Rapid diagnostic techniques such as ELISA and PCR offer an accurate and reproducible tool for early diagnosis and treatment of fungal pathogens.

Recognition and diagnosis of invasive fungal infections in neonates

Fungal infections largely caused by Candida species are responsible for a significant disease burden in neonates and invasive candidiasis in hospitalised neonates has high associated morbidity and mortality. Early initiation of antifungal treatment improves outcome but the recognition and diagnosis of systemic fungal infection in this population is difficult due to the non-specific clinical presentation and the high false negative rate of cultures. There is a need for a practical, sensitive and rapid diagnostic test to enhance identification and early treatment. Serum detection of (1,3)-β-d-glucan and Candida PCR are promising candidates but at present limited data exists for their use in the neonatal intensive care setting. Until such investigations are validated, early initiation of antifungal treatment on the basis of risk factor profile and clinical features remains the safest practical approach.

Systemic Fungal Infections in Patients with human inmunodeficiency virus

Histoplasmosis is a systemic infection caused by the dimorphic fungus Histoplasma capsulatum. In immunocompromised patients, primary pulmonary infection can spread to the skin and meninges. Clinical manifestations appear in patients with a CD4+ lymphocyte count of less than 150 cells/μL.Coccidioidomycosis is a systemic mycosis caused by Coccidioides immitis and Coccidioides posadasii. It can present as diffuse pulmonary disease or as a disseminated form primarily affecting the central nervous system, the bones, and the skin.Cryptococcosis is caused by Cryptococcus neoformans (var. neoformans and var. grubii) and Cryptococcus gattii, which are members of the Cryptococcus species complex and have 5 serotypes: A, B, C, D, and AD. It is a common opportunistic infection in patients with human immunodeficiency virus (HIV)/AIDS, even those receiving antiretroviral therapy.Histopathologic examination and culture of samples from any suspicious lesions are essential for the correct diagnosis of systemic fungal infections in patients with HIV/AIDS.

Micosis sistémicas en pacientes con virus de la inmunodeficiencia humana/sida

Histoplasmosis is a systemic infection caused by the dimorphic fungus Histoplasma capsulatum. In immunocompromised patients, primary pulmonary infection can spread to the skin and meninges. Clinical manifestations appear in patients with a CD4+ lymphocyte count of less than 150 cells/μL.Coccidioidomycosis is a systemic mycosis caused by Coccidioides immitis and Coccidioides posadasii. It can present as diffuse pulmonary disease or as a disseminated form primarily affecting the central nervous system, the bones, and the skin.Cryptococcosis is caused by Cryptococcus neoformans (var. neoformans and var. grubii) and Cryptococcus gattii, which are members of the Cryptococcus species complex and have 5 serotypes: A, B, C, D, and AD. It is a common opportunistic infection in patients with human immunodeficiency virus (HIV)/AIDS, even those receiving antiretroviral therapy.Histopathologic examination and culture of samples from any suspicious lesions are essential for the correct diagnosis of systemic fungal infections in patients with HIV/AIDS.

Diagnosis of Systemic Fungal Infection by Polymerase Chain Reaction Versus Conventional Blood Culture Method in Patients of Oncology Center Mansoura University

Diagnosis of Systemic Fungal Infection by Polymerase Chain Reaction Versus Conventional Blood Culture Method in Patients of Oncology Center Mansoura University

Speziesdiagnostik: Von der Agarplatte zur Molekularbiologie

During several decades microscopy and culture based methods have been the most important techniques for the detection of fungal infections. Culture, though often slow, sometimes insensitive and sometimes confusing with respect to contamination or colonization, may yield the specific aetiological agent, and may allow susceptibility testing to be performed. However, molecular detection and identification using PCR for the amplification of fungal DNA from tissue is being applied more and more frequently for the early diagnosis and identification of fungal pathogens. Other tools such as fluorescence in situ hybridization (FISH) or DNA microarrays have also been developed and their performance is currently being evaluated. Since standardization and validation for most of these newer techniques are still lacking the combination of various diagnostic tools is still mandatory to allow earlier diagnosis of systemic fungal infections.

Trends und neue Entwicklungen in der Diagnostik von Pilzinfektionen

Diagnosing fungal infections remains a problem, particularly in the immunocompromised patient. Symptoms are mostly non-specific and colonization is difficult to distinguish from invasive disease. Existing diagnostic tools often lack sensitivity. Thus, the combination of various diagnostic tools is mandatory to allow earlier diagnosis of systemic fungal infections. Microscopy, culture based methods, antigen detection and molecular techniques such as PCR may help to facilitate and accelerate the diagnosis. Sensitive and specific PCR assays to detect fungal DNA are an important part of the diagnostic approach. But extensive validation and standardization is strongly needed before PCR assays can be used in a routine laboratory.

Laboratory Diagnosis and Therapy of Invasive Fungal Infections

Diagnosing fungal infections remains a problem, particularly in the immunocompromised patient. Symptoms are mostly non-specific and colonization is difficult to distinguish from invasive disease. Existing diagnostic tools often lack sensitivity. Thus, the combination of various diagnostic tools is mandatory to allow earlier diagnosis of systemic fungal infections. Microscopy, culture based methods, antigen detection, and PCR may help to facilitate and accelerate the diagnosis. Galactomannan and glucan are two promising antigens that may be useful for early detection of the infection, but also for therapeutic monitoring. Sensitive and specific PCR assays to detect fungal DNA are an important part of the diagnostic approach. But extensive validation and standardization is strongly needed, before PCR assays can be used in a routine laboratory. The tremendous increase in invasive fungal infections has led to an increased interest in new antifungal agents and the field of antifungal chemotherapy evolved even more rapidly than diagnostic assays. The development of less toxic formulations of amphotericin B, the introduction of improved azoles and the availability of the echinocandins are opening new opportunities for the treatment of fungal infections. However, continuing efforts in the laboratory and well-designed clinical trials are still needed.

Aspergillus infection control in caring for BMT patients

Aspergillus is a ubiquitous soil-dwelling mould found in organic debris, compost, dust, rotted plants and food. There are approximately 200 species of aspergillus, some of which are pathogenic and cause aspergillosis (an infection, a growth, or an allergic response due to the aspergillus fungus). The aspergillus fungus grows best at 37 C and infection is acquired primarily through the inhalation of airborne spores entering the respiratory tract where the mould colonises to other sites (Soubani and Chandrasekar 2002; Linc et al 2001). Environmental factors such as water supply, inadequate filtration of outside air, and vacuum cleaning in hospital settings have been identified as risk factors for developing aspergillosis (Donnelly 2000; De La Rosa et al 2002). Bone marrow transplant (BMT) patients are by necessity immunocompromised, rendering them highly vulnerable to opportunistic infections. Aspergillosis is a common, life threatening complication of BMT, particularly in patients receiving grafts from unrelated donors, so called allogeneic transplants (Williamson et al 1999). Wingard (1999) suggests that with the availability of effective prophylaxis of bacterial and viral infections, invasive fungal infections have therefore become the major cause of infectious morbidity and mortality in patients undergoing BMT. Following BMT, the immune system recovers in a set pattern: cytolytic cells such as natural killer cells are first to recover followed by B-cell and then T-cell function. The time at which opportunistic infection by bacterial, viral, fungal and protozoal organisms occur can vary at different periods post transplant (Fox et al 2003; Wright-Kanuth and Smith 2001). Aspergillus can usually cause infection from day 20 to day 30 when the patient remains profoundly neutropenic post BMT (Patterson 1999; Wingard 1999; Maertens et al 2001). Fungal infections often follow bacterial infections if neutropenia continues (Linc et al 2001), and must be suspected if fever persists despite the usage of broad-spectrum antibiotic treatment (D’Antonio et al 1996). The diagnosis of systemic fungal infection in BMT patients is not straightforward due to the risks A bs tr ac t Many complications can occur following a bone marrow transplantation including that of opportunistic fungal infections such as aspergillus. This article discusses the care of a patient who was diagnosed with acute lymphoblastic leukaemia and subsequently received an allogeneic bone marrow transplant. A description of aspergillus infection and the interventions used to prevent and manage this complication are explored. Finally, the effectiveness of the care delivered is discussed along with the implications for future nursing practice.

POLYMERASE CHAIN REACTION BASED DIAGNOSIS OF SYSTEMIC FUNGAL INFECTIONS AND SENSITIVITY TESTING OF THE FUNGAL ISOLATES

Purpose: To highlight the usefulness of polymerase chain reaction (PCR) for the rapid diagnosis of systemic fungal infections. Methods: Clinical samples were collected from 50 clinically suspected cases of systemic mycosis and subjected to smear, culture, antifungal sensitivity and PCR (based on 18S rRNA gene). Results: Of the 50 clinical specimens tested by PCR, 39 were found to be positive. PCR gave more positive results than smear and culture examination. Out of the 50 clinical specimens 35 were found to be fungal culture positive. The sensitivity testing results of these fungal isolates showed that there was a good correlation between the in vitro results and the clinical response of the patient to antifungal therapy. Itraconazole exhibited maximum antifungal activity followed by fluconazole, ketoconazole and amphotericin B. Conclusions: PCR technology provides rapid and accurate diagnosis of fungal infection, however, it must be used with caution to avoid false positives.

Advances in serological systems for diagnosis of systemic fungal infections, particularly those caused by Candida and Aspergillus

Invasive fungal infections have emerged as important causes of morbidity and mortality in neutropenicand some other immunocompromised hosts; Candida and Aspergillus are among the major pathogens in this patient population. The clinical diagnosis of these infections is not specific and the traditional mycological methods for them not sensitive, with limits in the early detection of the pathogen. The potential additives or complements to the laboratory diagnosis of invasive candidiasis and aspergillosis are two non-culture-based methods, serodiagnostic methods and molecular ones. The former methods include the detection of pathogen-specific antigens, antibodies, metabolites and cell wall components. Several have already become standard laboratory tools and some others are under active investigation for developing new, more accurate detection systems. In this review, I will discuss the current status and future potential of serodiagnostic methods, highlighting both their technical and clinical implications.

Identification of medically significant fungal genera by polymerase chain reaction followed by restriction enzyme analysis

Rapid non-culture-dependent assays for identification of fungi quicken diagnosis and prompt treatment of invasive fungal disease. Fungal DNA extracts from pure cultures of the most frequently isolated fungal pathogens belonging to the Genera Aspergillus, Candida and Cryptococcus along with less common pathogenic Genera were amplified with the general fungal primer pair internal transcribed spacer-1/4. Subsequently, the amplicon was digested with the restriction endonucleases MspI, HaeIII, HinfI and EcoRI in order to generate genus- or species-specific patterns for identification of the fungus. HinfI produced indistinguishable fingerprints for all Aspergillus species tested. MspI produced species-specific patterns for: Cryptococcus neoformans, Cryptococcus non- neoformans, Candida albicans and Candida tropicalis. EcoRI succeeded in differentiating penicillia from aspergilli and cryptococci from Candida spp. It is concluded that this procedure can differentiate genera and occasionally species of medically important fungi and that following the necessary validation experiments, it can be used directly on clinical samples to assist prompt diagnosis of systemic fungal infections.

Identification of medically significant fungal genera by polymerase chain reaction followed by restriction enzyme analysis.

Rapid non-culture-dependent assays for identification of fungi quicken diagnosis and prompt treatment of invasive fungal disease. Fungal DNA extracts from pure cultures of the most frequently isolated fungal pathogens belonging to the Genera Aspergillus, Candida and Cryptococcus along with less common pathogenic Genera were amplified with the general fungal primer pair internal transcribed spacer-1/4. Subsequently, the amplicon was digested with the restriction endonucleases MspI, HaeIII, HinfI and EcoRI in order to generate genus- or species-specific patterns for identification of the fungus. HinfI produced indistinguishable fingerprints for all Aspergillus species tested. MspI produced species-specific patterns for: Cryptococcus neoformans, Cryptococcus non-neoformans, Candida albicans and Candida tropicalis. EcoRI succeeded in differentiating penicillia from aspergilli and cryptococci from Candida spp. It is concluded that this procedure can differentiate genera and occasionally species of medically important fungi and that following the necessary validation experiments, it can be used directly on clinical samples to assist prompt diagnosis of systemic fungal infections.

Clinical evaluation of diagnostic methods using plasma and/or serum for three mycoses: aspergillosis, candidosis, and pneumocystosis.

Clinical evaluation was retrospectively made of the results of serological diagnostic methods using plasma and/or sera of patients for the diagnosis of aspergillosis, candidosis, and pneumocystosis. Specimens were drawn from 8 patients with invasive aspergillosis, 3 with aspergilloma, 9 with candidosis, 4 with pneumocystosis, and 15 with no fungal infections. In invasive aspergillosis, the sensitivities of the (1-3)-beta-D-glucan measurement test using chromogenic and turbidimetric methods were 78.6% and 82.1%, with specificities of 75% and 87.5%, respectively. The sensitivity of the Pastorex Aspergillus test for invasive aspergillosis was 16.7%, with a specificity of 92.3%. In candidosis, the sensitivities of the (1-3)-bata-D-glucan test using the above two methods were 84.2% and 100%, with specificities of 75% and 87.5%, respectively. The sensitivity of the CAND-TEC test and the Pastorex Candida test for candidosis were 68.8% and 16.7%, with specificities of 57.1% and 100%, respectively. These results indicate that the (1-3)-bata-D-glucan measurement methods are more reliable in clinical application than the other antigen detection methods, but they still lack efficiency in differentiating fungal infections such as aspergillosis, candidosis and pneumocystosis. For a more exact diagnosis of systemic fungal infections, detailed studies on the clinical symptoms are considered essential.

Implications of Early Systemic Therapy on the Incidence of Endogenous Fungal Endophthalmitis

In the past, evidence of endogenous fungal endophthalmitis has been used as a guide to initiating potentially toxic antifungal therapy in patients with systemic fungal infections. Recently, however, a trend has developed to provide patients with antifungal therapy at the first evidence of fungal infection. The authors' study evaluates the incidence of endogenous fungal endophthalmitis in this setting. The design is a retrospective review of the medical records of patients examined by the inpatient ophthalmology consultation service to rule out endogenous fungal endophthalmitis between January 1994 and April 1996 at the University of Michigan Hospitals, Ann Arbor, Michigan. Two hundred fourteen eyes of 107 patients with a diagnosis of systemic fungal infection were studied. A review of medical records was performed. The findings of the ocular examination, the presence of risk factors for disseminated fungal infection, the type of antifungal therapy, and the source and identity of the isolated fungus were recorded. The majority of patients examined had either fungal growth from blood cultures or evidence of deep tissue fungal infection. All patients in the study were at risk for fungal disease with each having at least one risk factor for disseminated fungal infection. Of the patients examined, 93.4% already were receiving systemic antifungal therapy at the time of ophthalmologic consultation. Only 3 (2.8%) of the 107 patients examined had chorioretinal findings consistent with early endogenous fungal endophthalmitis. None had intravitreous involvement, and the ocular findings did not change the course of therapy. Early systemic treatment of deep tissue fungal infection appears to dramatically decrease the incidence of endogenous fungal endophthalmitis.

Early diagnosis of systemic fungal infection

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血液透析が深在性真菌症の血清診断におよぼす影響 β‐Ｄ‐グルカンとＤ‐アラビニトール

血液透析が深在性真菌症の血清診断 (β-D-グルカン, D-アラビニトール) に与える影響に関して肺アスペルギールス症, カンジダによる深在性真菌症を併発した慢性腎不全患者で検討した. 透析前後の血中および, 透析液また, 無作為に選んだダイアライザー充填液のβ-D-グルカン, D-アラビニトールを測定した. 透析の前後で血中β-D-グルカン (50.4±6.8, 56.7±4.3pg/ml, NS), D-アラビニトール/クレアチニン比 (1.8±0.13, 1.9±0.88μmol/mg, NS) は変化しなかった. 充填液中のβ-D-グルカンは10.0±2.3pg/mlであった.血液透析はβ-D-グルカン, D/C比に影響を与えない. Wet type, dry typeのキュプラアンモニウムレーヨン透析膜のリムルステスト陽性物質の血中移行の差は中空糸製造過程で生ずると考えられる.

Buffy coat smears of blood drawn through central venous catheters as an aid to rapid diagnosis of systemic fungal infections

Buffy coat smears of blood drawn through central venous catheters as an aid to rapid diagnosis of systemic fungal infections

Identification of fungal casts in a patient with renal candidiasis

Since the treatment of fungal infections with amphotericin B may result in significant nephrotoxicity, better methods for discriminating between life-threatening and more benign fungal infections are needed. Recently numerous fungal casts were identified in the urine of a patient who had undergone renal allograft transplantation. The recognition of fungal casts permitted an unequivocal diagnosis of systemic fungal infection. Successive examinations of the patient's urinary sediment provided an excellent monitor of the response to treatment. The cytologic features of fungal casts are described. Since systemic fungal infections often involve the kidney, screening for fungal casts may have significant clinical applicability.

Candida antibodies in heart surgery patients

Summary One hundred and twenty-three cardiac surgery patients were screened pre-operatively and 7–10 days post-operatively for Candida serum antibodies. The average perioperative rise in agglutination titre and in precipitin response was not related to any fungal or bacterial infection, nor to any reported pyrexial episodes. Individual responses revealed a wide scatter in response and there was a general similarity between agglutination and precipitin changes. Patients with pyrexial episodes or bacterial endocarditis had a higher incidence (20 per cent) of commensal or superficial fungal growth than most of the group (5–8 per cent). The non-specific rise in Candida serum antibodies was found to be common. It is seen as a possible source of confusion in the diagnosis of systemic fungal infection associated with major cardiac surgery.