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Rhino-orbital-cerebral mucormycosis (ROCM) is linked to uncontrolled diabetes, diabetic ketoacidosis, iron overload, corticosteroid therapy, and neutropenia. This study evaluated a commercial real-time PCR system's effectiveness in detecting Mucorales from nasal swabs in 50 high-risk patients. Nasal swab PCR showed 30% positivity, compared to 8% with KOH microscopy. Despite its improved sensitivity, nasal swab PCR has limitations, highlighting the importance of established sampling methods in mucormycosis diagnosis. Participants were predominantly male (64%), with diabetes (78%) and amphotericin B use (96%). Prior COVID-19 was 42%, with 30% positive for Mucorales by PCR, compared to 8% with KOH microscopy.
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Mucorales , Mucormicose , Reação em Cadeia da Polimerase em Tempo Real , Humanos , Mucormicose/diagnóstico , Masculino , Feminino , Reação em Cadeia da Polimerase em Tempo Real/métodos , Mucorales/isolamento & purificação , Mucorales/genética , Pessoa de Meia-Idade , Adulto , COVID-19/diagnóstico , Sensibilidade e Especificidade , Idoso , SARS-CoV-2/genética , SARS-CoV-2/isolamento & purificaçãoRESUMO
Unusual fungi, encountered infrequently in practice, present a significant diagnostic challenge, leading to potential delays in diagnosis and treatment. This study aims to describe a number of cases, where infections were caused by rare yeast pathogens. Organisms isolated included rare Candida species, Geotrichum, Lodderomyces and Trichosporon species. The mean duration of the outcome of the patients from microbiological diagnosis was 20 days. A total of 3 patients succumbed to their illness. This study aims to shed light on the varied clinical presentation and outcome of infections caused by rare yeast pathogens.
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Micoses , Humanos , Masculino , Micoses/microbiologia , Micoses/diagnóstico , Feminino , Adulto , Pessoa de Meia-Idade , Leveduras/isolamento & purificação , Leveduras/classificação , Trichosporon/isolamento & purificação , Trichosporon/classificação , Trichosporon/genética , Geotrichum/isolamento & purificação , Candida/isolamento & purificação , Candida/classificação , Criança , Resultado do Tratamento , AdolescenteRESUMO
Aim: Currently, we have limited armamentarium of antifungal agents against Mucorales. There is an urgent need to discover novel antifungal agents that are effective, safe and affordable. Materials & methods: In this study, the anti-Mucorale action of native lactoferrin (LF) and its functional fragments CLF, RR6 and LFcin against three common Mucorale species are reported. The synergistic action of LF with antifungal agents like amphotericin B, isavuconazole and posaconazole was analyzed using checkerboard technique. Results: All the three mucor species showed inhibition when treated with fragments. The checkerboard assay confirmed that native LF showed the best synergistic action against Mucorales in combination with Amphotericin B. Conclusion: These results highlight the potential therapeutic value of native LF against Mucorales.
Black fungus, or 'mucormycosis', is a dangerous fungal infection. Normally, it affects people with a weakened immune system. It is only treatable when diagnosed early. It spreads by breathing the fungus in, eating contaminated food or direct contact with an infected wound. There are not many medicines that can treat this type of fungus, so it is important to find new ones. In this study, we tested a natural protein called lactoferrin and some of its building blocks, called peptides, to see if they could stop the fungus from growing. Lactoferrin and its peptides could stop the fungus from growing, especially when used with a medicine called amphotericin B. This means that lactoferrin could potentially be a helpful treatment for this fungal infection.
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Anfotericina B , Antifúngicos , Sinergismo Farmacológico , Lactoferrina , Testes de Sensibilidade Microbiana , Mucormicose , Lactoferrina/farmacologia , Lactoferrina/uso terapêutico , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Mucormicose/tratamento farmacológico , Mucormicose/microbiologia , Anfotericina B/farmacologia , Humanos , Triazóis/farmacologia , Triazóis/uso terapêutico , Mucorales/efeitos dos fármacos , Mucor/efeitos dos fármacos , Piridinas/farmacologia , Piridinas/uso terapêutico , Nitrilas/farmacologia , Nitrilas/uso terapêuticoRESUMO
BACKGROUND: Data on mixed mould infection with COVID-19-associated pulmonary aspergillosis (CAPA) and COVID-19-associated pulmonary mucormycosis (CAPM) are sparse. OBJECTIVES: To ascertain the prevalence of co-existent CAPA in CAPM (mixed mould infection) and whether mixed mould infection is associated with early mortality (≤7 days of diagnosis). METHODS: We retrospectively analysed the data collected from 25 centres across India on COVID-19-associated mucormycosis. We included only CAPM and excluded subjects with disseminated or rhino-orbital mucormycosis. We defined co-existent CAPA if a respiratory specimen showed septate hyphae on smear, histopathology or culture grew Aspergillus spp. We also compare the demography, predisposing factors, severity of COVID-19, and management of CAPM patients with and without CAPA. Using a case-control design, we assess whether mixed mould infection (primary exposure) were associated with early mortality in CAPM. RESULTS: We included 105 patients with CAPM. The prevalence of mixed mould infection was 20% (21/105). Patients with mixed mould infection experienced early mortality (9/21 [42.9%] vs. 15/84 [17.9%]; p = 0.02) and poorer survival at 6 weeks (7/21 [33.3] vs. 46/77 [59.7%]; p = 0.03) than CAPM alone. On imaging, consolidation was more commonly encountered with mixed mould infections than CAPM. Co-existent CAPA (odds ratio [95% confidence interval], 19.1 [2.62-139.1]) was independently associated with early mortality in CAPM after adjusting for hypoxemia during COVID-19 and other factors. CONCLUSION: Coinfection of CAPA and CAPM was not uncommon in our CAPM patients and portends a worse prognosis. Prospective studies from different countries are required to know the impact of mixed mould infection.
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COVID-19 , Coinfecção , Mucormicose , Humanos , COVID-19/complicações , COVID-19/mortalidade , Mucormicose/mortalidade , Mucormicose/epidemiologia , Mucormicose/complicações , Masculino , Feminino , Estudos Retrospectivos , Pessoa de Meia-Idade , Prevalência , Coinfecção/mortalidade , Coinfecção/epidemiologia , Coinfecção/microbiologia , Índia/epidemiologia , Adulto , Aspergilose Pulmonar/complicações , Aspergilose Pulmonar/mortalidade , Aspergilose Pulmonar/epidemiologia , SARS-CoV-2 , Idoso , Estudos de Casos e Controles , Pneumopatias Fúngicas/mortalidade , Pneumopatias Fúngicas/complicações , Pneumopatias Fúngicas/epidemiologiaRESUMO
A 3-year-old patient in India experiencing headaches and seizures was diagnosed with a fungal infection, initially misidentified as Cladophialophora bantiana. Follow-up sequencing identified the isolate to be Fonsecaea monophora fungus. This case demonstrates the use of molecular methods for the correct identification of F. monophora, an agent of fungal brain abscess.
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Ascomicetos , Abscesso Encefálico , Abscesso Encefálico/microbiologia , Abscesso Encefálico/diagnóstico , Abscesso Encefálico/tratamento farmacológico , Humanos , Ascomicetos/isolamento & purificação , Ascomicetos/genética , Ascomicetos/classificação , Pré-Escolar , Masculino , Micoses/microbiologia , Micoses/diagnóstico , Antifúngicos/uso terapêutico , Antifúngicos/farmacologia , Filogenia , DNA Fúngico/genéticaRESUMO
BACKGROUND: Chronic pulmonary aspergillosis (CPA) is known to complicate patients with post-tubercular lung disease. However, some evidence suggests that CPA might co-exist in patients with newly-diagnosed pulmonary tuberculosis (P.TB) at diagnosis and also develop during therapy. The objective of this study was to confirm the presence of CPA in newly diagnosed P.TB at baseline and at the end-of-TB-therapy. MATERIALS AND METHODS: This prospective longitudinal study included newly diagnosed P.TB patients, followed up at third month and end-of-TB-therapy with symptom assessment, anti-Aspergillus IgG antibody and imaging of chest for diagnosing CPA. RESULTS: We recruited 255 patients at baseline out of which 158 (62%) completed their follow-up. Anti-Aspergillus IgG was positive in 11.1% at baseline and 27.8% at end-of-TB-therapy. Overall, proven CPA was diagnosed in 7% at baseline and 14.5% at the end-of-TB-therapy. Around 6% patients had evidence of aspergilloma in CT chest at the end-of-TB-therapy. CONCLUSIONS: CPA can be present in newly diagnosed P.TB patients at diagnosis and also develop during anti-tubercular treatment. Patients with persistent symptoms or developing new symptoms during treatment for P.TB should be evaluated for CPA. Whether patients with concomitant P.TB and CPA, while receiving antitubercular therapy, need additional antifungal therapy, needs to be evaluated in future studies.
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Aspergilose Pulmonar , Tuberculose Pulmonar , Humanos , Masculino , Feminino , Aspergilose Pulmonar/epidemiologia , Aspergilose Pulmonar/tratamento farmacológico , Aspergilose Pulmonar/complicações , Aspergilose Pulmonar/diagnóstico , Tuberculose Pulmonar/tratamento farmacológico , Tuberculose Pulmonar/complicações , Tuberculose Pulmonar/epidemiologia , Tuberculose Pulmonar/diagnóstico , Pessoa de Meia-Idade , Estudos Prospectivos , Adulto , Estudos Longitudinais , Incidência , Idoso , Anticorpos Antifúngicos/sangue , Doença Crônica , Seguimentos , Imunoglobulina G/sangue , Antituberculosos/uso terapêutico , Aspergillus/isolamento & purificação , Aspergillus/imunologia , Adulto JovemRESUMO
Coronavirus disease 2019 (COVID-19) associated mucormycosis (CAM) was reported predominantly from India during the second wave of COVID-19 and has a high mortality rate. The present study aims to understand the fungal community composition of the nasopharyngeal region of CAM-infected individuals and compare it with severe COVID-19 patients and healthy controls. The fungal community composition was decoded by analyzing the sequence homology of the internal transcribed spacer-2-(ITS-2) region of metagenomic DNA extracted from the upper respiratory samples. The alpha-diversity indices were found to be significantly altered in CAM patients (p < 0.05). Interestingly, a higher abundance of Candida africana, Candida haemuloni, Starmerella floris, and Starmerella lactiscondensi was observed exclusively in CAM patients. The interindividual changes in mycobiome composition were well supported by beta-diversity analysis (p < 0.05). The current study provides insights into the dysbiosis of the nasal mycobiome during CAM infection. In conclusion, our study shows that severe COVID-19 and CAM are associated with alteration in mycobiome as compared to healthy controls. However, the sequential alteration in the fungal flora which ultimately leads to the development of CAM needs to be addressed by future studies.
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COVID-19 , Mucormicose , Micobioma , Humanos , Mucormicose/epidemiologia , Nariz , Índia/epidemiologiaRESUMO
INTRODUCTION: Invasive mould infections (IMIs) are a leading cause of death in patients with compromised immune systems. Proven invasive mould infection requires detection of a fungus by histopathological analysis of a biopsied specimen, sterile culture, or fungal DNA amplification by PCR in tissue. However, the clinical performance of a PCR assay on blood samples taken from patients suspected of invasive mould disease has not been fully evaluated, particularly for the differential diagnosis of invasive aspergillosis (IA) and invasive Mucormycosis (IM). OBJECTIVES: To assess the diagnostic utility of our previously validated in-house real-time PCR in blood samples for diagnosis of invasive aspergillosis and mucormycosis in patients with suspected invasive mould infection. METHODS: All patients with suspected invasive mould infection were prospectively enrolled from May 2021 to July 2021. Conventional fungal diagnosis was performed using tissue and respiratory samples. In-house PCR was performed on blood samples and its diagnostic performance evaluated. RESULTS: A total of 158 cases of suspected invasive mould infection were enrolled in the study. The sensitivity and specificity of in-house PCR performed on blood samples was found to be 92.5% and 81.4% respectively for diagnosis of probable IA, and 65% and 84.62% respectively for diagnosis of proven and probable IM. It was also able to detect 3 out of 5 cases of possible IM where no other microbiological evidence of IM was obtained. CONCLUSIONS: This assay could be helpful in minimally invasive diagnosis of IMIs for patients in whom invasive sampling is not feasible, especially as a preliminary or screening test. It can help in early diagnosis, anticipating conventional laboratory confirmation by days or weeks. Possible correlation between fungal load and mortality can help in initiating aggressive treatment for patients with high initial fungal load.
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Infecções Fúngicas Invasivas , Mucormicose , Reação em Cadeia da Polimerase em Tempo Real , Sensibilidade e Especificidade , Humanos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Feminino , Masculino , Pessoa de Meia-Idade , Mucormicose/diagnóstico , Mucormicose/microbiologia , Mucormicose/sangue , Adulto , Estudos Prospectivos , Idoso , Infecções Fúngicas Invasivas/diagnóstico , Infecções Fúngicas Invasivas/microbiologia , Infecções Fúngicas Invasivas/sangue , DNA Fúngico/sangue , DNA Fúngico/genética , Aspergilose/diagnóstico , Aspergilose/microbiologia , Aspergilose/sangue , Diagnóstico Precoce , Adulto Jovem , Idoso de 80 Anos ou mais , Diagnóstico DiferencialRESUMO
A 3-year-old boy presented with acute headache, vomiting and right focal clonic seizures without history of fever, joint pain or altered sensorium. Neuroimaging showed multifocal contrast enhancing lesions with significant perilesional edema. CECT chest and abdomen showed multiple variable sized nodules in the lungs and hypodense lesion in liver with mesenteric lymphadenopathy. There was persistent eosinophilia with maximum upto 35 %. Liver biopsy and brain biopsy revealed Cladophialophora bantiana. He was treated with IV liposomal amphotericin and voriconazole for 6 weeks with repeat neuroimaging showing more than 50 % resolution of the intracranial lesions. He was transitioned to oral combination of flucytosine and voriconazole. At 14 months follow-up, he remained symptom free with complete radiological resolution of the lesions and no eosinophilia. High suspicion, an aggressive approach in obtaining microbiological diagnosis and timely combination antifungal therapy may give satisfactory outcome without surgery.
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Anfotericina B , Antifúngicos , Ascomicetos , Imunocompetência , Feoifomicose , Humanos , Masculino , Pré-Escolar , Antifúngicos/uso terapêutico , Ascomicetos/isolamento & purificação , Feoifomicose/microbiologia , Feoifomicose/diagnóstico , Feoifomicose/tratamento farmacológico , Anfotericina B/uso terapêutico , Voriconazol/uso terapêutico , Flucitosina/uso terapêutico , Flucitosina/administração & dosagemRESUMO
BACKGROUND: Fungal infections are now a great public health threat, especially in those with underlying risk factors such as neutropenia, diabetes, high-dose steroid treatment, cancer chemotherapy, prolonged intensive care unit stay, and so on, which can lead to mycoses with higher mortality rates. The rates of these infections have been steadily increasing over the past 2 decades due to the increasing population of patients who are immunocompromised. However, the data regarding the exact burden of such infection are still not available from India. Therefore, this registry was initiated to collate systematic data on invasive fungal infections (IFIs) across the country. OBJECTIVE: The primary aim of this study is to create a multicenter digital clinical registry and monitor trends of IFIs and emerging fungal diseases, as well as early signals of any potential fungal outbreak in any region. The registry will also capture information on the antifungal resistance patterns and the contribution of fungal infections on overall morbidity and inpatient mortality across various conditions. METHODS: This multicenter, prospective, noninterventional observational study will be conducted by the Indian Council of Medical Research through a web-based data collection method from 8 Advanced Mycology Diagnostic and Research Centers across the country. Data on age, gender, clinical signs and symptoms, date of admission, date of discharge or death, diagnostic tests performed, identified pathogen details, antifungal susceptibility testing, outcome, and so on will be obtained from hospital records. Descriptive and multivariate statistical methods will be applied to investigate clinical manifestations, risk variables, and treatment outcomes. RESULTS: These Advanced Mycology Diagnostic and Research Centers are expected to find the hidden cases of fungal infections in the intensive care unit setting. The study will facilitate the enhancement of the precision of fungal infection diagnosis and prompt treatment modalities in response to antifungal drug sensitivity tests. This registry will improve our understanding of IFIs, support evidence-based clinical decision-making ability, and encourage public health policies and actions. CONCLUSIONS: Fungal diseases are a neglected public health problem. Fewer diagnostic facilities, scanty published data, and increased vulnerable patient groups make the situation worse. This is the first systematic clinical registry of IFIs in India. Data generated from this registry will increase our understanding related to the diagnosis, treatment, and prevention of fungal diseases in India by addressing pertinent gaps in mycology. This initiative will ensure a visible impact on public health in the country. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/54672.
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Mucormycosis is a rare disease with scarce diagnostic methods for early intervention. Available strategies employing direct microscopy using calcofluor white-KOH, culture, radiologic, and histopathologic testing often are time-intensive and demand intricate protocols. Nucleic Acid Amplification Test holds promise due to its high sensitivity combined with rapid detection. Loop-mediated isothermal amplification (LAMP) based detection offers an ultrasensitive technique that does not require complicated thermocyclers like in polymerase chain reaction, offering a straightforward means for improving diagnoses as a near-point-of-care test. The study introduces a novel magnetic nanoparticle-based LAMP assay for carryover contaminant capture to reduce false positives. Solving the main drawback of LAMP-based diagnosis techniques. The assay targets the cotH gene, which is invariably specific to Mucorales. The assay was tested with various species of Mucorales, and the limit of detections for Rhizopus microsporus, Lichtheimia corymbifera, Rhizopus arrhizus, Rhizopus homothallicus, and Cunninghamella bertholletiae were 1 fg, 1 fg, 0.1 pg, 0.1 pg, and 0.01 ng, respectively. This was followed by a clinical blindfolded study using whole blood and urine samples from 30 patients diagnosed with Mucormycosis. The assay has a high degree of repeatability and had an overall sensitivity of > 83%. Early Mucormycosis detection is crucial, as current lab tests from blood and urine lack sensitivity and take days for confirmation despite rapid progression and severe complications. Our developed technique enables the confirmation of Mucormycosis infection in < 45 min, focusing specifically on the RT-LAMP process. Consequently, this research offers a viable technique for quickly identifying Mucormycosis from isolated DNA of blood and urine samples instead of invasive tissue samples.
Mucormycosis is a challenging disease to diagnose early. This study introduces a sensitive and rapid diagnostic approach using Loop-mediated isothermal amplification technology. Testing blood and urine samples from 30 patients revealed promising sensitivity and repeatability, indicating its potential for non-invasive diagnosis.
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Nanopartículas de Magnetita , Mucorales , Mucormicose , Humanos , Mucormicose/diagnóstico , Mucormicose/veterinária , Sensibilidade e Especificidade , Técnicas de Amplificação de Ácido Nucleico/métodos , Técnicas de Amplificação de Ácido Nucleico/veterinária , Técnicas de Diagnóstico Molecular/métodos , Técnicas de Diagnóstico Molecular/veterinária , Mucorales/genéticaRESUMO
BACKGROUND: Bronchoalveolar lavage (BAL) galactomannan (GM) is commonly used to diagnose Aspergillus-related lung diseases. However, unlike serum GM, which is measured in undiluted blood, BAL-GM is estimated using variable aliquots and cumulative volume of instillates during bronchoscopy. OBJECTIVE: Since different studies have reported varying diagnostic accuracy and cut-offs for BAL-GM in CPA, we hypothesized that the total volume of instillate and 'order/label' of aliquots significantly affects the BAL-GM values, which was evaluated as part of this study. PATIENTS & METHODS: We obtained 250 BAL samples from 50 patients (five from each) with suspected chronic pulmonary aspergillosis. BAL fluid was collected after instilling sequential volumes of 40 mL of normal saline each for the first four labels and a fifth label was prepared by mixing 1 mL from each of the previous labels. The GM level of each label was measured by PLATELIA™ ASPERGILLUS Ag enzyme immunoassay. This study measured the discordance, level of agreement, diagnostic characteristics (sensitivity, specificity and AUROC) and best cut-offs for BAL-GM in the different aliquots of lavage fluid. RESULTS: The study population, classified into CPA (28%) and non-CPA (72%) groups, based on ERS/ESCMID criteria (excluding BAL-GM) were not different with respect to clinico-radiological characteristics. The discordance of BAL-GM positivity (using a cut-off of >1) between the serial labels for the same patient ranged between 10% and 22%, while the discordance between classification using BAL-GM positivity (using a cut-off of ≥1) and clinic-radio-microbiological classification ranged between 18% and 30%. The level of agreement for serial labels was at best fair (<0.6 for all except one 'label'). The AUROC for the serial samples ranged between 0.595 and 0.702, with the '40 mL and the 'mix' samples performing the best. The best BAL-GM cut-off also showed significant variation between serial labels of varying dilutions (Range:1.01 - 4.26). INTERPRETATION: This study highlights the variation in BAL-GM measured and the 'positivity' between different 'labels' of aliquots of BAL, with the first aliquot and the mixed sample showing the best performances for diagnosis of CPA. Future studies should attempt to 'standardise' the instilled volume for BAL-GM estimation to standardise the diagnostic yield.
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Galactose/análogos & derivados , Aspergilose Pulmonar Invasiva , Aspergilose Pulmonar , Humanos , Projetos Piloto , Sensibilidade e Especificidade , Aspergilose Pulmonar/diagnóstico , Lavagem Broncoalveolar , Líquido da Lavagem Broncoalveolar/microbiologia , Mananas , Infecção Persistente , Aspergilose Pulmonar Invasiva/diagnóstico , Aspergilose Pulmonar Invasiva/microbiologiaRESUMO
A well-structured digital database is essential for any national priority project as it can provide real-time data analysis and facilitate quick decision making. In recent times, particularly after the COVID-19 pandemic, invasive fungal infections (IFIs) have emerged as a significant public health challenge in India, affecting vulnerable population, including immunocompromised individuals. The lack of comprehensive and well-structured data on IFIs has hindered efforts to understand their true burden and optimize patient care. To address this critical knowledge gap, the ICMR has undertaken a Pan-India pioneer initiative to develop a network of Advanced Mycology Diagnostic research centres in different geographical zones of the country (ICMR-MycoNet). Under the aegis of this project, a clinical registry on IFIs in the ICUs is initiated. This process paper presents a detailed account of the steps involved in the establishment of a web-based data entering and monitoring platform to capture data electronically, ensuring robust and secure data collection and management. This system not only allows participating ICMR-MycoNet centres to enter patient information directly into the database using standardized Case Report Form (CRF) but also includes data validation checks to ensure the accuracy and completeness of entered data. It is complemented by a real-time, web-based, and adaptable data visualization platform. This registry aims to provide crucial epidemiological insights, promote evidence-based hospital infection control programs, and ultimately improve patient outcomes in the face of this formidable healthcare challenge.
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INTRODUCTION: Voriconazole is a triazole anti-fungal with non-linear kinetics and a narrow therapeutic range. The objective of our study was to monitor the voriconazole serum levels in children with hematological malignancy and clinically suspected invasive fungal infections. METHODS: The study was a prospective, randomized controlled trial conducted from June 2016 to December 2017. All children who had haematologic malignancies with clinically suspected invasive fungal infections and received voriconazole as the only anti-fungal were included in the study. The children were randomly allotted into two groups; one was the group that underwent TDM, and the other, TDM, was not done. Bioassay was the method employed for TDM. The trough levels were evaluated on a sample obtained on the fifth day of starting the drug. The institute's ethics committee approved the study. RESULT: A total of 30 children were included in the study: 15 in the TDM group and 15 in the non-TDM group. The most common underlying malignancy was AML. Neutropenia due to chemotherapy sessions was these patients' most common risk factor. A favorable outcome was seen in 13/15 (86.7%) in the TDM group and 11/15 in the non-TDM group (73.3%). CONCLUSION: Only five out of 15 (33.3%) children had voriconazole serum levels within the therapeutic range. Alterations in dose had to be done in the remaining to achieve the recommended serum levels. Thus, we recommend TDM for all children of hematologic malignancy receiving voriconazole for better management. Our findings also revealed that children with AML had lower than recommended levels of voriconazole on TDM evaluation, whereas those with ALL had normal to elevated levels of voriconazole.
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Neoplasias Hematológicas , Infecções Fúngicas Invasivas , Leucemia Mieloide Aguda , Criança , Humanos , Voriconazol/uso terapêutico , Monitoramento de Medicamentos , Centros de Atenção Terciária , Estudos Prospectivos , Neoplasias Hematológicas/complicações , Neoplasias Hematológicas/tratamento farmacológico , Índia , Infecções Fúngicas Invasivas/tratamento farmacológicoRESUMO
Cryptococcus neoformans is an important opportunistic fungal pathogen that causes life-threatening infection of the central nervous system. A major virulence factor for C. neoformans is the production of melanin in the cell wall. Using transmission electron microscopy, we studied the cell walls of three pairs of isolates obtained from patients with dual cryptococcal infections, where a melanotic and an albino strain were isolated from the CSF of each patient. Transmission Electron Microscopy revealed that the albino strains lacked a melanin layer whereas a melanin layer was associated with the cell wall of the melanotic strains, comprising approximately 75 percent of the cell wall area. The cell wall size of the melanin producing cells was approximately double the size the albino isolates' cell walls (p value <= 0.003). In this study TEM revealed that the differences in the ultrastructure of the melanin lacking and melanin producing isolates were associated to the cell wall and the melanin layer.
Cryptococcus neoformans é um importante fungo oportunista patogênico que causa infecção no sistema nervoso central, e que pode levar o paciente à morte. Um dos principais fatores de virulência do C. neoformans é a produção de melanina na parede celular. Utilizando microscopia eletrônica de transmissão, nós estudamos as paredes celulares de três pares de isolados obtidos de pacientes com dupla infecção pelo fungo, onde um isolado melanizado e um albino foram isolados do líquor de cada paciente. A microscopia eletrônica de transmissão revelou que as cepas albinas não apresentavam a camada de melanina enquanto que uma camada de melanina estava associada com a parede celular de cepas melanóticas, constituindo aproximadamente 75 por cento da área da parede celular. O tamanho da parede celular das células produtoras de melanina foi aproximadamente o dobro do tamanho da parede celular dos isolados albinos (p < 0,003). Neste estudo, a microscopia eletrônica de transmissão revelou que as diferenças na estrutura dos isolados albinos sem melanina e dos isolados produtores de melanina estava associada à parede celular e a camada de melanina.