Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-19 (of 19 Records) |
Query Trace: Gomez BL[original query] |
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Application of real-time PCR assays for the diagnosis of histoplasmosis in human FFPE tissues using three molecular targets
López LF , Tobón Á M , Cáceres DH , Chiller T , Litvintseva AP , Gade L , González Á , Gómez BL . J Fungi (Basel) 2023 9 (7) Histoplasmosis is a fungal infection caused by the thermally dimorphic fungus Histoplasma capsulatum. This infection causes significant morbidity and mortality in people living with HIV/AIDS, especially in countries with limited resources. Currently used diagnostic tests rely on culture and serology but with some limitations. No molecular assays are commercially available and the results from different reports have been variable. We aimed to evaluate quantitative real-time PCR (qPCR) targeting three protein-coding genes of Histoplasma capsulatum (100-kDa, H and M antigens) for detection of this fungus in formalin-fixed paraffin-embedded (FFPE) samples from patients with proven histoplasmosis. The sensitivity of 100-kDa, H and M qPCR assays were 93.9%, 91% and 57%, respectively. The specificity of 100-kDa qPCR was 93% when compared against samples from patients with other mycoses and other infections, and 100% when samples from patients with non-infectious diseases were used as controls. Our findings demonstrate that real-time PCR assays targeting 100-kDa and H antigen showed the most reliable results and can be successfully used for diagnosing this mycosis when testing FFPE samples. |
Tackling histoplasmosis infection in people living with HIV from Latin America: From diagnostic strategy to public health solutions
Cáceres DH , Gómez BL , Tobón Á M , Restrepo Á , Chiller T , Lindsley MD , Meis JF , Verweij PE . J Fungi (Basel) 2023 9 (5) Histoplasmosis, caused by the thermally dimorphic fungus Histoplasma spp., is a disease with a broad clinical spectrum, presenting from asymptomatic/flu-like symptoms to progressive disseminated disease in people with immunosuppression. In recent years, the concept of histoplasmosis as a disease restricted to the American continent has changed, as now histoplasmosis is reported in many regions around the world. In Latin America, histoplasmosis represents a threat, especially in people with advanced HIV disease (AHD). Diagnosis of histoplasmosis in people living with HIV (PLHIV) is challenging due to the low index of suspicion of the disease, non-specificity of signs and symptoms, and limited access to specific laboratory testing, while the diagnostic delay is significantly associated with mortality. In the last decade, novel diagnostic tests have been developed for the rapid detection of histoplasmosis, such as commercial kits for antigen detection. Furthermore, advocacy groups were created that presented histoplasmosis as a public health problem, with emphasis on patients at risk of progressive disseminated disease. This review aims to discuss the impact of histoplasmosis associated with AHD in Latin America and the strategies employed to tackle histoplasmosis, from the implementation of laboratory testing to disease advocacy and public health interventions. |
Validation and concordance analysis of a new lateral flow assay for detection of histoplasma antigen in urine
Cáceres DH , Gómez BL , Tobón Á M , Minderman M , Bridges N , Chiller T , Lindsley MD . J Fungi (Basel) 2021 7 (10) Histoplasmosis is a major cause of mortality in people living with HIV (PLHIV). Rapid methods to diagnose Histoplasma capsulatum disease could dramatically decrease the time to initiate treatment, resulting in reduced mortality. The aim of this study was to validate a MiraVista(®) Diagnostics (MVD) Histoplasma urine antigen lateral flow assay (MVD LFA) for the detection of H. capsulatum antigen (Ag) in urine and compare this LFA against the MVista(®) Histoplasma Ag quantitative enzyme immunoassays (MVD EIA). We assessed the MVD LFA using a standardized reference panel of urine specimens from Colombia. We tested 100 urine specimens, 26 from PLHIV diagnosed with histoplasmosis, 42 from PLHIV with other infectious diseases, and 32 from non-HIV infected persons without histoplasmosis. Sensitivity and specificity of the MVD LFA was 96%, compared with 96% sensitivity and 77% specificity of the MVD EIA. Concordance analysis between MVD LFA and the MVD EIA displayed an 84% agreement, and a Kappa of 0.656. The MVD LFA evaluated in this study has several advantages, including a turnaround time for results of approximately 40 min, no need for complex laboratory infrastructure or highly trained laboratory personnel, use of urine specimens, and ease of performing. |
Current situation of endemic mycosis in the Americas and the Caribbean: Proceedings of the first International Meeting On Endemic Mycoses Of The Americas (IMEMA)
Caceres DH , EcheverriTirado LC , Bonifaz A , Adenis A , Gomez BL , Flores CLB , Canteros CE , Santos DW , Arathoon E , Soto ER , Queiroz-Telles F , Schwartz IS , Zurita J , Damasceno LS , Garcia N , Fernandez NB , Chincha O , Araujo P , Rabagliati R , Chiller T , Giusiano G . Mycoses 2022 65 (12) 1179-1187 BACKGROUND: The Americas are home to biologically and clinically diverse endemic fungi, including Blastomyces, Coccidioides, Emergomyces, Histoplasma, Paracoccidioides and Sporothrix. In endemic areas with high risk of infection, these fungal pathogens represent an important public health problem. OBJECTIVES: This report aims to summarise the main findings of the regional analysis carried out on the status of the endemic mycoses of the Americas, done at the first International Meeting on Endemic Mycoses of the Americas (IMEMA). METHODS: A regional analysis for the Americas was done, the 27 territories were grouped into nine regions. A SWOT analysis was done. RESULTS: All territories reported availability of microscopy. Seventy percent of territories reported antibody testing, 67% of territories reported availability of Histoplasma antigen testing. None of the territories reported the use of (1-3)--d-glucan. Fifty two percent of territories reported the availability of PCR testing in reference centres (mostly for histoplasmosis). Most of the territories reported access to medications such as trimethoprim-sulfamethoxazole, itraconazole, voriconazole and amphotericin B (AMB) deoxycholate. Many countries had limited access to liposomal formulation of AMB and newer azoles, such as posaconazole and isavuconazole. Surveillance of these fungal diseases was minimal. CONCLUSIONS: A consensus emerged among meeting participants, this group concluded that endemic mycoses are neglected diseases, and due to their severity and lack of resources, the improvement of diagnosis, treatment and surveillance is needed. |
Evaluation of OIDx Histoplasma Urinary Antigen EIA
Cáceres DH , Gómez BL , Tobón Á M , Chiller TM , Lindsley MD . Mycopathologia 2021 187 (1) 129-131 A sandwich enzyme immunoassay (EIA) for the detection of Histoplasma antigens (Ag) in urine, developed by Optimum Imaging Diagnostics (OIDx) was evaluated. A verification using a standardized reference panel of urine samples found sensitivity of 92%, specificity of 32% and accuracy of 51%. In this study, the OIDx Histoplasma urinary Ag EIA displayed high sensitivity, however, in non-histoplasmosis cases this EIA displayed false-positive results in 68% of specimens tested. |
Summary of guidelines for managing histoplasmosis among people living with HIV
Perez F , Caceres DH , Ford N , Ravasi G , Gomez BL , Pasqualotto AC , Hine P , Adenis AA , Nacher M , Chiller T , Baddley J . J Fungi (Basel) 2021 7 (2) Histoplasmosis is a frequent fungal opportunistic infection in people living with HIV (PLHIV), associated every year to a total of 5% to 15% of AIDS-related deaths among this population. In 2020, the first global guidelines for diagnosing and managing disseminated histoplasmosis among PLHIV was published. This document recommends (1) detection of circulating Histoplasma antigens as the recommended laboratory assay to diagnose histoplasmosis among PLHIV; (2) the use of liposomal amphotericin for induction therapy in severe or moderately severe disease, followed by a maintenance therapy with itraconazole for 12 months; a shorter maintenance therapy could be considered if the patient is clinically stable and if immune status has improved; (3) antiretroviral therapy initiation as soon as possible among patients with histoplasmosis without involvement of central nervous system; and (4) that for the treatment of co-infection with histoplasmosis and tuberculosis (TB), treatment of TB should be initiated according to the World Health Organization treatment guidelines. Appropriate health education of providers, supportive supervision, and policy guidance for the care of PLHIV are required. |
The Manaus Declaration: Current Situation of Histoplasmosis in the Americas, Report of the II Regional Meeting of the International Histoplasmosis Advocacy Group
Caceres DH , Adenis A , de Souza JVB , Gomez BL , Cruz KS , Pasqualotto AC , Ravasi G , Perez F , Chiller T , de Lacerda MVG , Nacher M . Curr Fungal Infect Rep 2019 13 (4) 244-249 Purpose of Review: The aim of this report is to summarize the conclusions of the II Regional Meeting on Histoplasmosis in the Americas held in Manaus, Brazil, on March 22–24, 2019. Recent Findings: Persons living with advanced HIV are at high risk for developing histoplasmosis. Clinical signs and symptoms of this disease are often non-specific, making it difficult to establish a diagnosis. Although with the recent technological advances, in vitro diagnostics and medicines for histoplasmosis are often not available in many regions around the world. In addition, histoplasmosis is often not included in HIV care and treatment programs, resulting in inadequate health system planning and missed opportunities to save lives. Summary: The II Regional Meeting on Histoplasmosis in the Americas gathered a multidisciplinary audience. Developed recommendations to be included in the WHO guidelines for diagnosis and treatment of histoplasmosis in advanced HIV were the product of this meeting, and guidelines are aimed to be published in early 2020. |
Evaluation of a Histoplasma antigen Lateral Flow Assay for the rapid diagnosis of progressive disseminated histoplasmosis in Colombian patients with AIDS
Caceres DH , Gomez BL , Tobon AM , Chiller TM , Lindsley MD . Mycoses 2019 63 (2) 139-144 BACKGROUND: Progressive disseminated histoplasmosis (PDH) is an important cause of mortality in persons living with HIV (PLHIV), especially in countries where patients have limited access to antiretroviral therapies and diagnostic testing. OBJECTIVE: A Lateral Flow Assay (LFA) to detect Histoplasma capsulatum antigen in serum developed by MiraVista((R)) was evaluated. METHODS: We tested 75 serum samples: 24 from PLHIV and culture-proven PDH and 51 from PLHIV with other fungal and bacterial infections as well as people without HIV. LFA devices were read manually (read by eye) and by an automated reader. RESULTS: When the LFA was read manually, sensitivity was 96% and specificity was 90%. When an automated reader was used, sensitivity was 92% and specificity was 94%. The Kappa index comparing manual and automated reader was 0.90. Cross-reactions were observed principally in samples from patients with proven diagnosis of paracoccidioidomycosis. CONCLUSIONS: The MiraVista((R)) Diagnostics Histoplasma antigen LFA had high analytical performance and good agreement between manual and automated reader. This LFA allows Histoplasma antigen testing with minimal laboratory equipment and infrastructure requirements. |
The Diagnosis of Fungal Neglected Tropical Diseases (Fungal NTDs) and the Role of Investigation and Laboratory Tests: An Expert Consensus Report.
Hay R , Denning DW , Bonifaz A , Queiroz-Telles F , Beer K , Bustamante B , Chakrabarti A , Chavez-Lopez MG , Chiller T , Cornet M , Estrada R , Estrada-Chavez G , Fahal A , Gomez BL , Li R , Mahabeer Y , Mosam A , Soavina Ramarozatovo L , Rakoto Andrianarivelo M , Rapelanoro Rabenja F , van de Sande W , Zijlstra EE . Trop Med Infect Dis 2019 4 (4) The diagnosis of fungal Neglected Tropical Diseases (NTD) is primarily based on initial visual recognition of a suspected case followed by confirmatory laboratory testing, which is often limited to specialized facilities. Although molecular and serodiagnostic tools have advanced, a substantial gap remains between the desirable and the practical in endemic settings. To explore this issue further, we conducted a survey of subject matter experts on the optimal diagnostic methods sufficient to initiate treatment in well-equipped versus basic healthcare settings, as well as optimal sampling methods, for three fungal NTDs: mycetoma, chromoblastomycosis, and sporotrichosis. A survey of 23 centres found consensus on the key role of semi-invasive sampling methods such as biopsy diagnosis as compared with swabs or impression smears, and on the importance of histopathology, direct microscopy, and culture for mycetoma and chromoblastomycosis confirmation in well-equipped laboratories. In basic healthcare settings, direct microscopy combined with clinical signs were reported to be the most useful diagnostic indicators to prompt referral for treatment. The survey identified that the diagnosis of sporotrichosis is the most problematic with poor sensitivity across the most widely available laboratory tests except fungal culture, highlighting the need to improve mycological diagnostic capacity and to develop innovative diagnostic solutions. Fungal microscopy and culture are now recognized as WHO essential diagnostic tests and better training in their application will help improve the situation. For mycetoma and sporotrichosis, in particular, advances in identifying specific marker antigens or genomic sequences may pave the way for new laboratory-based or point-of-care tests, although this is a formidable task given the large number of different organisms that can cause fungal NTDs. |
Concordance analysis between different methodologies used for identification of oral isolates of Candida species
Zuluaga A , Arango-Bustamante K , Caceres DH , Sanchez-Quitian ZA , Velasquez V , Gomez BL , Parra-Giraldo CM , Maldonado N , Cano LE , de Bedout C , Rivera RE . Colomb Med (Cali) 2018 49 (3) 193-200 Background: The yeasts species determination is fundamental not only for an accurate diagnosis but also for establishing a suitable patient treatment. We performed a concordance study of five methodologies for the species identification of oral isolates of Candida in Colombia. Methods: Sixty-seven Candida isolates were tested by; API(R) 20C-AUX, Vitek(R)2 Compact, Vitek(R)MS, Microflex(R) and a molecular test (panfungal PCR and sequencing). The commercial cost and processing time of the samples was done by graphical analysis. Results: Panfungal PCR differentiated 12 species of Candida, Vitek(R)MS and Microflex(R) methods identified 9 species, and API(R) 20C-AUX and Vitek(R)2 Compact methods identified 8 species each. Weighted Kappa (wK) showed a high agreement between Panfungal PCR, Vitek(R)MS, Microflex(R) and API(R) 20C-AUX (wK 0.62-0.93). The wK that involved the Vitek(R)2 Compact method presented moderate or good concordances compared with the other methods (wK 0.56-0.73). Methodologies based on MALDI TOF MS required 4 minutes to generate results and the Microflex(R) method had the lowest selling price. Conclusion: The methods evaluated showed high concordance in their results, being higher for the molecular methods and the methodologies based on MALDI TOF. The latter are faster and cheaper, presenting as promising alternatives for the routine identification of yeast species of the genus Candida. |
Multicenter validation of commercial antigenuria reagents to diagnose progressive disseminated histoplasmosis in people living with HIV/AIDS in two Latin American countries
Caceres DH , Samayoa BE , Medina NG , Tobon AM , Guzman BJ , Mercado D , Restrepo A , Chiller T , Arathoon EE , Gomez BL . J Clin Microbiol 2018 56 (6) Histoplasmosis is an important cause of mortality in patients with AIDS, especially in countries with limited access to antiretroviral therapies and diagnostic tests. However, many disseminated infections in Latin America go undiagnosed. A simple, rapid method to detect Histoplasma capsulatum infection in endemic regions would dramatically decrease time to diagnosis and treatment, reducing morbidity and mortality. The aim of this study was to validate a commercial monoclonal Histoplasma galactomannan (HGM) ELISA (Immuno-Mycologics [IMMY], Norman, Oklahoma, USA) in two cohorts of people living with HIV/AIDS (PLHIV). We analyzed urine samples from 589 people (466 from Guatemala and 123 from Colombia), including 546 from PLHIV and 43 from non-PLHIV controls. Sixty-three of these people (35 from Guatemala and 28 from Colombia) had confirmed histoplasmosis by isolation of H. capsulatum Using the standard curve provided by the quantitative commercial test, sensitivity was 98% (95% CI, 95-100) and specificity was 97% (95% CI, 96-99) (cutoff=0.5 ng/mL). Semi-quantitative results, using a calibrator of 12.5 ng/mL of Histoplasma galactomannan to calculate an EIA Index Value (EIV) of the samples, showed a sensitivity of 95% (95% CI, 89-100%) and specificity of 98% (95% CI, 96-99%) (cutoff >/=2.6 EIV). This relatively simple-to-perform commercial antigenuria test showed a high performance, with reproducible results in both countries, suggesting that it can used to detect progressive disseminated histoplasmosis in PLHIV in a wide range of clinical laboratories in countries where histoplasmosis is endemic. |
The important role of co-infections in patients with AIDS and progressive disseminated histoplasmosis (PDH): A cohort from Colombia
Caceres DH , Tobon A M , Restrepo A , Chiller T , Gómez BL . Med Mycol Case Rep 2018 19 41-44 A total of 23/45 (51%) patients with AIDS and histoplasmosis from Medellín, Colombia had other infections. Tuberculosis was the most common (n = 16/23, 70%). Pneumocystosis and cryptococcosis were found in three patients each (13%), bacterial infection and cytomegalovirus occurred each in two patients (9%) while toxoplasmosis, herpes virus and esophageal candidiasis were recorded in one patient each (4%). Of all co-infected patients, 18/23 (78%) had one, four (17%) had two and one (4%) had three additional opportunistic infections. |
Standardization and validation of real time PCR assays for the diagnosis of histoplasmosis using three molecular targets in an animal model.
Lopez LF , Munoz CO , Caceres DH , Tobon AM , Loparev V , Clay O , Chiller T , Litvintseva A , Gade L , Gonzalez A , Gomez BL . PLoS One 2017 12 (12) e0190311 Histoplasmosis is considered one of the most important endemic and systemic mycoses worldwide. Until now few molecular techniques have been developed for its diagnosis. The aim of this study was to develop and evaluate three real time PCR (qPCR) protocols for different protein-coding genes (100-kDa, H and M antigens) using an animal model. Fresh and formalin-fixed and paraffin-embedded (FFPE) lung tissues from BALB/c mice inoculated i.n. with 2.5x106 Histoplasma capsulatum yeast or PBS were obtained at 1, 2, 3, 4, 8, 12 and 16 weeks post-infection. A collection of DNA from cultures representing different clades of H. capsulatum (30 strains) and other medically relevant pathogens (36 strains of related fungi and Mycobacterium tuberculosis) were used to analyze sensitivity and specificity. Analytical sensitivity and specificity were 100% when DNAs from the different strains were tested. The highest fungal burden occurred at first week post-infection and complete fungal clearance was observed after the third week; similar results were obtained when the presence of H. capsulatum yeast cells was demonstrated in histopathological analysis. In the first week post-infection, all fresh and FFPE lung tissues from H. capsulatum-infected animals were positive for the qPCR protocols tested except for the M antigen protocol, which gave variable results when fresh lung tissue samples were analyzed. In the second week, all qPCR protocols showed variable results for both fresh and FFPE tissues. Samples from the infected mice at the remaining times post-infection and uninfected mice (controls) were negative for all protocols. Good agreement was observed between CFUs, histopathological analysis and qPCR results for the 100-kDa and H antigen protocols. We successfully standardized and validated three qPCR assays for detecting H. capsulatum DNA in fresh and FFPE tissues, and conclude that the 100-kDa and H antigen molecular assays are promising tests for diagnosing this mycosis. |
Evaluation of a Cryptococcal antigen Lateral Flow Assay in serum and cerebrospinal fluid for rapid diagnosis of cryptococcosis in Colombia
Caceres DH , Zuluaga A , Tabares AM , Chiller T , Gonzalez A , Gomez BL . Rev Inst Med Trop Sao Paulo 2017 59 e76 A Lateral Flow Assay to detect cryptococcal antigen (CrAg(R) LFA) in serum and cerebrospinal fluid for the rapid diagnosis of cryptococcosis was evaluated. A retrospective validation was performed. Sensitivity and specificity of the CrAg(R) LFA was 100%. High concordance (kappa index=1.0) between Cryptococcal Antigen Latex Agglutination System (CALAS(R)) and CrAg(R) LFA was observed. CrAg(R) LFA showed higher analytical sensitivity for detecting low concentrations of cryptococcal antigen. |
High mortality and coinfection in a prospective cohort of human immunodeficiency virus/acquired immune deficiency syndrome patients with histoplasmosis in Guatemala
Samayoa B , Roy M , Cleveland AA , Medina N , Lau-Bonilla D , Scheel CM , Gomez BL , Chiller T , Arathoon E . Am J Trop Med Hyg 2017 97 (1) 42-48 Histoplasmosis is one of the most common and deadly opportunistic infections among persons living with human immunodeficiency virus (HIV)/acquired immune deficiency syndrome in Latin America, but due to limited diagnostic capacity in this region, few data on the burden and clinical characteristics of this disease exist. Between 2005 and 2009, we enrolled patients ≥ 18 years of age with suspected histoplasmosis at a hospital-based HIV clinic in Guatemala City. A case of suspected histoplasmosis was defined as a person presenting with at least three of five clinical or radiologic criteria. A confirmed case of histoplasmosis was defined as a person with a positive culture or urine antigen test for Histoplasma capsulatum. Demographic and clinical data were also collected and analyzed. Of 263 enrolled as suspected cases of histoplasmosis, 101 (38.4%) were confirmed cases. Median time to diagnosis was 15 days after presentation (interquartile range [IQR] = 5-23). Crude overall mortality was 43.6%; median survival time was 19 days (IQR = 4-69). Mycobacterial infection was diagnosed in 70 (26.6%) cases; 26 (25.7%) histoplasmosis cases were coinfected with mycobacteria. High mortality and short survival time after initial symptoms were observed in patients with histoplasmosis. Mycobacterial coinfection diagnoses were frequent, highlighting the importance of pursuing diagnoses for both diseases. |
Clinical and laboratory profile of persons living with human immunodeficiency virus/acquired immune deficiency syndrome and histoplasmosis from a Colombian hospital
Caceres DH , Tobon AM , Cleveland AA , Scheel CM , Berbesi DY , Ochoa J , Restrepo A , Brandt ME , Chiller T , Gomez BL . Am J Trop Med Hyg 2016 95 (4) 918-924 Histoplasmosis is common among persons living with human immunodeficiency virus/acquired immune deficiency syndrome (PLWHA) in Latin America, but its diagnosis is difficult and often nonspecific. We conducted prospective screening for histoplasmosis among PLWHA with signs or symptoms suggesting progressive disseminated histoplasmosis (PDH) and hospitalized in Hospital La Maria in Medellin, Colombia. The study's aim was to obtain a clinical and laboratory profile of PLWHA with PDH. During 3 years (May 2008 to August 2011), we identified 89 PLWHA hospitalized with symptoms suggestive of PDH, of whom 45 (51%) had histoplasmosis. We observed tuberculosis (TB) coinfection in a large proportion of patients with PDH (35%), so all analyses were performed adjusting for this coinfection and, alternatively, excluding histoplasmosis patients with TB. Results showed that the patients with PDH were more likely to have Karnofsky score ≤ 30 (prevalence ratio [PR] = 1.98, 95% confidence interval [CI] = 0.97-4.06), liver compromised with hepatomegaly and/or splenomegaly (PR = 1.77, CI = 1.03-3.06) and elevation in serum of alanine aminotransferase and aspartate aminotransferase to values > 40 mU/mL (PR = 2.06, CI = 1.09-3.88 and PR = 1.53, CI = 0.99-2.35, respectively). Using multiple correspondence analyses, we identified in patients with PDH a profile characterized by the presence of constitutional symptoms, namely weight loss and Karnofsky classification ≤ 30, gastrointestinal manifestations with alteration of liver enzymes and hepatosplenomegaly and/or splenomegaly, skin lesions, and hematological alterations. Study of the profiles is no substitute for laboratory diagnostics, but identifying clinical and laboratory indicators of PLWHA with PDH should allow development of strategies for reducing the time to diagnosis and thus mortality caused by Histoplasma capsulatum. |
Whole-Genome Sequencing to Determine Origin of Multinational Outbreak of Sarocladium kiliense Bloodstream Infections.
Etienne KA , Roe CC , Smith RM , Vallabhaneni S , Duarte C , Escadon P , Castaneda E , Gomez BL , de Bedout C , Lopez LF , Salas V , Hederra LM , Fernandez J , Pidal P , Hormazabel JC , Otaiza F , Vannberg FO , Gillece J , Lemmer D , Driebe EM , Englethaler DM , Litvintseva AP . Emerg Infect Dis 2016 22 (3) 476-81 We used whole-genome sequence typing (WGST) to investigate an outbreak of Sarocladium kiliense bloodstream infections (BSI) associated with receipt of contaminated antinausea medication among oncology patients in Colombia and Chile during 2013-2014. Twenty-five outbreak isolates (18 from patients and 7 from medication vials) and 11 control isolates unrelated to this outbreak were subjected to WGST to elucidate a source of infection. All outbreak isolates were nearly indistinguishable (<5 single-nucleotide polymorphisms), and >21,000 single-nucleotide polymorphisms were identified from unrelated control isolates, suggesting a point source for this outbreak. S. kiliense has been previously implicated in healthcare-related infections; however, the lack of available typing methods has precluded the ability to substantiate point sources. WGST for outbreak investigation caused by eukaryotic pathogens without reference genomes or existing genotyping methods enables accurate source identification to guide implementation of appropriate control and prevention measures. |
Validation of a histoplasma ELISA antigenuria test in Colombian patients with AIDS for diagnosis and follow-up during therapy
Caceres DH , Scheel CM , Tobon AM , Ahlquist Cleveland A , Restrepo A , Brandt ME , Chiller T , Gomez BL . Clin Vaccine Immunol 2014 We validated an antigen capture ELISA test in Colombian persons with AIDS and proven histoplasmosis, and evaluated the correlation between antigenuria and clinical improvement during follow up. The sensitivity of the H. capsulatum ELISA was 86% and the overall specificity was 94%. The antigen test successfully monitored response to therapy. |
Validation and clinical application of a molecular method for the identification of Histoplasma capsulatum in human specimens in Colombia, South America
Munoz C , Gomez BL , Tobon A , Arango K , Restrepo A , Correa MM , Muskus C , Cano LE , Gonzalez A . Clin Vaccine Immunol 2009 17 (1) 62-7 Conventional diagnosis of histoplasmosis presents difficulties delaying diagnosis, indicating the need for implementation of molecular assays. We evaluated 146 clinical samples from 135 patients suspected to have histoplasmosis using a previously reported nested PCR assay (Hc100). In order to determine the specificity of this molecular test, we also used samples from healthy individuals (n=20), from patients suspected to have respiratory disease with negative fungal cultures (n=29), and patients with other proven infections (n=60). Additionally, a sizable collection of DNA from cultures of H.capsulatum and other medically relevant pathogens were studied. A panfungal PCR assay amplifying the ITS2 region was also used to identify all fungal DNAs. All PCR amplified products were sequenced. From the 146 clinical samples, 67 (45.9%) were positive by culture and PCR, while 9 samples negative by culture were positive by PCR. All the sequences corresponding to the 76 amplified products presented ≥98% identity with H.capsulatum. The Hc100 PCR exhibited a sensitivity of 100% and a specificity of 92.4% and 95.2% when compared to negative controls nd to samples from other proven clinical entities, respectively; PPV was 83% and NPV was 100%; the positive and negative likelihood rates were 25 and 0, respectively. These results suggest that the Hc100-based nested PCR assay for detection of H.capsulatum DNA is a useful test in areas where this mycosis is endemic. |
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