Etiología, clínica y evolución de infecciones fúngicas invasoras en pacientes con neoplasias hematológicas en un hospital universitario de Argentina

Introducción: Las infecciones fúngicas invasoras (IFI) en pacientes con neoplasias hematológicas (NH) representan un desafío diagnóstico y terapéutico. Objetivos: Describir la etiología, características clínicas, diagnóstico y evolución de los episodios de IFI probadas y probables en pacientes con NH y trasplante de progenitores hematopoyéticos (TPH). Pacientes y Métodos: Estudio descriptivo, retrospectivo y de cohorte que incluyó IFI probadas y probables en pacientes adultos con NH y TPH. Se realizó seguimiento hasta el día 90. Resultados: Se incluyeron 80 episodios de IFI: 49% probadas y 51% probables, 67,5% por hongos filamentosos (HF), 30% por hongos levaduriformes (HL) y 2,5% por hongos dimorfos. Los tipos de IFI más frecuentes fueron aspergilosis invasoras pulmonares (AP) y candidiasis invasoras (CI), en su mayoría por Candida spp. no albicans. Todos los casos de AP se diagnosticaron por detección de galactomanano en sangre y/o lavado broncoalveolar, y solamente 22,2% presentaban nódulos con halo en la tomografía computada (TC) de tórax, siendo los infiltrados inespecíficos los hallazgos más frecuentes. Tuvieron coinfección bacteriana y viral el 30 y 17,5%, respectivamente. El 50% fueron IFI de brecha, y la mortalidad global y mortalidad relacionada a la IFI fue 51 y 24%, respectivamente. Conclusión: Los HF fueron la principal causa de IFI, con una gran proporción de IFI de brecha, y presentaron elevada mortalidad. Para el diagnóstico, resulta importante la utilización de biomarcadores y jerarquizar cualquier imagen patológica en la TC.

Background: Invasive fungal infections (IFI) in patients with hematological malignancies (HM) represent a diagnostic and therapeutic challenge. Aim: To describe the etiology, clinical characteristics, diagnosis and evolution of proven and probable IFI episodes in patients with HM and hematopoietic stem cell transplantation (HSCT). Methods: Retrospective, descriptive, cohort study performed in adult patients with HM and HSCT, who developed proven and probable IFI. Follow-up was carried out until day 90. Results: A total of 80 IFI episodes were included: 49% proven and 51% probable, 67,5% due to mold (M), 30% to yeast-like fungi (Y) and 2,5% to dimorphic fungi. The most frequent causes were probable pulmonary aspergillosis (PA) and invasive candidiasis (IC), mainly due to non-albicans Candida species. PA were all diagnosed by detection of galactomannan (GM) in blood and bronchoalveolar lavage, and only 22,2% presented halo sign on chest CT. Bacterial and viral coinfections were reported in 30% and 17,5% respectively. Breakthrough IFI occurred in 50%, and global and IFI-related mortality were 51% and 24% respectively. Conclusion: Mold was the main cause of IFI, with a large proportion of breakthrough IFI, presenting high mortality. The use of biomarkers and the classification of any pathological image on CT contribute to the diagnosis.

Evaluation of the MALDI-TOF mass spectrometry technique for the identification of dermatophytes: Use of an extended database.

BACKGROUND: Identification of dermatophytes is usually performed through morphological analyses. However, it may be hindered due to the discovery of new species and complexes and, with some isolates, by the absence of fructification. Matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) seems to be an option for improving identification. AIMS: To develop a database (DB) for the identification of dermatophytes with MALDI-TOF MS, including 32 isolates from the Red de Micología de la Ciudad Autónoma de Buenos Aires [Mycology Network of the Autonomous City of Buenos Aires] (RMCABA) and one reference isolate (RMCABA DB), and evaluate its performance when added to the DB from the supplier, Bruker (Bruker DB). METHODS: All the isolates in the RMCABA DB were identified based on morphology and sequencing. To evaluate the performance of the extended DB (Bruker DB plus RMCABA DB), 136 clinical isolates were included. RESULTS: The percentages of identification at the species level increased from 45% to 88%, but the identification at the genus level decreased from 23% to 7%. CONCLUSIONS: MALDI-TOF MS yielded better performance in the identification of dermatophytes after including the RMCABA DB, which encompassed local isolates.

Sporotrichosis in Argentina: clinical and epidemiological analysis / Esporotricosis en Argentina: análisis clínico y epidemiológico

Introduction: Sporotrichosis is an implantation mycosis caused by Sporothrix spp. It is distributed worldwide and can be found in vegetation and soil. The most frequent route of infection is by trauma with elements contaminated with fungal propagules. Since domestic cats are the most affected animals and can transmit this infection to humans, sporotrichosis is considered a zoonosis. Clinical presentations include nodular lymphangitis, fixed cutaneous, pulmonary (rare), and disseminated (exceptional). Objectives: To analyze the epidemiology of sporotrichosis in Argentina during 2010 and 2022. To describe the clinical presentation, diagnostic methods, and treatment of cases diagnosed during this period. To know the circulating genotypes and to observe possible associations with the geographic location where the infection was acquired. Materials and methods: Analytical, retrospective, and observational study. We analyzed the medical records of patients with sporotrichosis from 12 health institutions in Argentina, between 2010 and 2022. Results: We present 54 cases in which the most frequent clinical form was nodular lymphangitis, and the treatment of choice was itraconazole. Conventional diagnosis was made in all cases. Culture of clinical samples was more sensitive than direct examination because it allowed the isolation of Sporothrix spp. in all 54 cases. Molecular identification was performed in 22 cases, with Sporothrix schenkii sensu stricto being the most frequently isolated species. Conclusions: This study allowed to know the epidemiology of this mycosis in Argentina, as well as the availability of diagnostic methods and the treatment of choice.

Introducción: La esporotricosis es una micosis de implantación causada por Sporothrix spp. Este se encuentra distribuido mundialmente y se puede encontrar en la vegetación y en el suelo. La ruta más frecuente de adquisición de la infección es por traumatismos con elementos contaminados con propágulos del hongo. Los gatos domésticos son los animales más afectados y pueden transmitirla a los humanos, por lo que es considerada una zoonosis. Las formas clínicas incluyen: la linfangítica nodular, la cutánea fija, la pulmonar (poco habitual) y la diseminada (excepcional). Objetivo: Analizar la epidemiología de la esporotricosis en Argentina entre los años 2010 y 2022. Describir la presentación clínica, los métodos de diagnóstico y el tratamiento de los casos diagnosticados en este período. Conocer los genotipos circulantes y observar su relación con el lugar geográfico de adquisición de la infección. Materiales y métodos. Se llevó a cabo un estudio analítico, retrospectivo y observacional, en el que se analizaron las historias clínicas de los pacientes con esporotricosis de 12 instituciones de salud de Argentina, entre los años 2010 y 2022. Resultados: Se presentan 54 casos en los que la forma clínica más frecuente fue la linfangítica nodular y el tratamiento de elección fue el itraconazol. En todos los casos se realizó diagnóstico convencional. El cultivo de las muestras clínicas resultó más sensible que el examen directo, ya que permitió el desarrollo de Sporothrix spp. en los 54 casos. En 22 casos se hizo identificación molecular y Sporothrix schenkii sensu stricto fue la especie más frecuentemente aislada. Conclusiones: Este estudio permitió conocer la epidemiología de esta micosis en Argentina, así como la disponibilidad de métodos diagnósticos y el tratamiento de elección.

Evaluation of the MALDI-TOF mass spectrometry technique for the identification of dermatophytes: Use of an extended database / Evaluación de la técnica de espectrometría de masas MALDI-TOF para la identificación de dermatofitos: utilización de una base de datos ampliada

Background: Identification of dermatophytes is usually performed through morphological analyses. However, it may be hindered due to the discovery of new species and complexes and, with some isolates, by the absence of fructification. Matrix-assisted laser desorption/ionisation-time-of-flight mass spectrometry (MALDI-TOF MS) seems to be an option for improving identification. Aims: To develop a database (DB) for the identification of dermatophytes with MALDI-TOF MS, including 32 isolates from the Red de Micología de la Ciudad Autónoma de Buenos Aires [Mycology Network of the Autonomous City of Buenos Aires] (RMCABA) and one reference isolate (RMCABA DB), and evaluate its performance when added to the DB from the supplier, Bruker (Bruker DB). Methods: All the isolates in the RMCABA DB were identified based on morphology and sequencing. To evaluate the performance of the extended DB (Bruker DB plus RMCABA DB), 136 clinical isolates were included. Results: The percentages of identification at the species level increased from 45% to 88%, but the identification at the genus level decreased from 23% to 7%.Conclusions: MALDI-TOF MS yielded better performance in the identification of dermatophytes after including the RMCABA DB, which encompassed local isolates.(AU)

Antecedentes: La identificación de dermatofitos se realiza, usualmente, a través del análisis morfológico, pero puede verse dificultada por la aparición de nuevas especies y complejos de especies y, en algunos aislamientos, por la falta de elementos de fructificación. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) aparece como una alternativa para mejorar la identificación. Objetivos: Construir una base de datos (BaDa) para la identificación de dermatofitos mediante MALDI-TOF MS, con 32 aislamientos de la Red de Micología de la Ciudad Autónoma de Buenos Aires (RMCABA) y una cepa de referencia (BaDa RMCABA), y evaluar su desempeño al incorporarla a la BaDa del proveedor Bruker (BaDa Bruker). Métodos: Todos los aislamientos incorporados a la BaDa RMCABA se identificaron por morfología y secuenciación. Para la evaluación de la BaDa ampliada (BaDa Bruker más BaDa RMCABA) se incluyeron 136 aislamientos clínicos. Resultados: El porcentaje de identificación a nivel de especie se incrementó del 45 al 88%, mientras que la identificación a nivel de género disminuyó del 23 al 7%. Conclusiones: Con la incorporación de la BaDa RMCABA, que contó con aislamientos regionales, se observó un mejor desempeño en la identificación de dermatofitos por MALDI-TOF MS.(AU)

Short Course of Antibiotic Therapy for Gram-Negative Bacilli Bacteremia in Patients with Cancer and Hematopoietic Stem Cell Transplantation: Less Is Possible.

Data about short courses of antibiotic therapy for Gram-negative bacilli (GNB) bacteremia in immunosuppressed patients are limited. This is a prospective observational study performed on adult patients with cancer and hematopoietic stem cell transplant (HSCT) who developed GNB bacteremia and received appropriate empirical antibiotic therapy (EAT), had a clinical response within 7 days and survived 48 h after the end of therapy. They received antibiotic therapy in the range of 7-15 days and were divided into short course, with a median of 7 days (SC), or long course, with a median of 14 days (LC). Seventy-four patients were included (SC: 36 and LC: 38). No differences were observed in baseline characteristics or in the presence of neutropenia: 58.3% vs. 60.5% (p = 0.84). Clinical presentation and microbiological characteristics were similar in SC and LC, respectively: clinical source of bacteremia 72.2% vs. 76.3% (p = 0.68); shock 2.8% vs. 10.5% (p = 0.35) and multidrug-resistant GNB 27.8% vs. 21.1% (p = 0.50). Overall, mortality was 2.8% vs. 7.9% (p = 0.61), and bacteremia relapse was 2.8% vs. 0 (p = 0.30). The length of hospitalization since bacteremia was 7 days (interquartile range (IQR), 6-15) for SC and 12 days (IQR, 7-19) (p = 0.021) for LC. In the case of patients with cancer or HSCT and GNB bacteremia who receive appropriate EAT with clinical response, 7 days of antibiotic therapy might be adequate.

Outbreak of Klebsiella pneumoniae ST11 Resistant To Ceftazidime-Avibactam Producing KPC-31 and the Novel Variant KPC-115 during COVID-19 Pandemic in Argentina.

We describe an outbreak of Klebsiella pneumoniae sequence type 11 (ST11) producing KPC variants resistant to ceftazidime-avibactam. Six patients hospitalized in the intensive care unit (mostly due to critical COVID pneumonia) presented infection or colonization by this bacterium. They had several comorbidities and required mechanical ventilation, central venous catheters, and urinary catheters. All 6 patients had a history of fecal colonization with KPC-producing Enterobacterales (KPC-E). Three of them had previous episodes of infection with ceftazidime-avibactam-susceptible KPC-producing K. pneumoniae, which were treated with ceftazidime-avibactam. Several phenotypic methods failed to detect carbapenemase production in these 6 ceftazidime-avibactam-resistant isolates, and they showed in vitro susceptibility to imipenem and meropenem. All of them rendered positive results for blaKPC by PCR, and amplicon sequencing identified blaKPC-31 variant in 5 isolates and a novel variant, named blaKPC-115, in the other. Moreover, matrix-assisted laser desorption ionization-time of flight mass spectrometry was able to detect KPC in all isolates. Ceftazidime-avibactam-resistant isolates, as well as those recovered from previous infection episodes (KPC-3-producing K. pneumoniae, ceftazidime-avibactam susceptible), displayed a unique pulse type and belonged to ST11. Based on whole-genome sequencing results of selected isolates, less than 7 single-nucleotide polymorphisms were identified among them, which was indicative of the presence of a unique clone. Both in vivo selection and horizontal transmission seemed to have occurred in our hospital. Detection of these strains is challenging for the laboratory. History of previous KPC-E infections or colonization and systematic testing for resistance to ceftazidime-avibactam might help raise awareness of this possibility. IMPORTANCE Klebsiella pneumoniae is one of the main bacteria that cause infections in health care settings. This pathogen has developed a high level of resistance to many antibiotics. Some K. pneumoniae isolates can produce an enzyme known as carbapenemase KPC, making carbapenems (considered the last line for therapy) not effective to treat their infections. The combination ceftazidime-avibactam, approved by FDA in 2015, is useful to treat infections caused by KPC-producing K. pneumoniae. This study describes the emergence, in one hospital in Argentina, of K. pneumoniae isolates that produce KPC variants (KPC-31 and KPC-115) resistant to ceftazidime-avibactam. The ceftazidime-avibactam-resistant bacteria were isolated in inpatients, including some that previously received this combination as treatment. Transmission of this strain to other patients also occurred in the studied period. Detection of these bacteria is challenging for the laboratory. The knowledge and awareness of the emergence of this pathogen in our region are highly valuable.

Identificación directa de microorganismos a partir de hemocultivos positivos utilizando espectrometría de masas (MALDI-TOF MS) / Direct identification of microorganisms in positive blood culture bottles by mass spectrometry (MALDI-TOF MS)

Resumen La espectrometría de masas (MALDI-TOF MS) permite la identificación de microorganismos directamente de las colonias en pocos minutos. En este estudio se ha desarrollado y evaluado un protocolo reducido para identificar microorganismos directamente de las botellas de hemocultivos positivos en 30 minutos con una alta sensibilidad y especificidad, utilizando MALDITOF. Un total de 2535 hemocultivos positivos fueron estudiados por el método directo de MALDI-TOF MS, a partir de una alícuota de sangre de las botellas y el método de colonia, utilizando los cultivos desarrollados en medios sólidos. Del total de hemocultivos positivos incluidos en este estudio, 2381 (93,9%) fueron monomicrobianos y 146 (5,8%) polimicrobianos. Mil trescientos treinta (55,9%) de los aislamientos correspondieron a cocos gram positivos, 922 (38,7%) a bacilos gram negativos, 60 (2,5%) a anaerobios, 36 (1,5%) a bacilos gram positivos y 13 a levaduras. La concordancia global entre ambos métodos fue del 81,7% a nivel de especie (90,0% para bacilos gram negativos, 76,7% para cocos gram positivos y 33,3% para bacilos gram positivos). Se identificó al menos un germen en el 88% de las botellas positivas con desarrollo polimicrobiano. Los resultados del presente estudio demostraron que el protocolo basado en MALDI-TOF MS permite la identificación microbiana directamente de hemocultivos positivos en un tiempo corto, con una alta precisión, con excepción de los bacilos gram positivos.

Abstract Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) enables the identification of microorganisms directly from colonies within minutes. In this study this technology was adapted and tested for use with blood culture bottles, thus allowing identification in 30 minutes once the blood culture is detected as positive by the automate. A total of 2535 blood culture bottles reported as positive were tested by MALDI-TOF MS directly from positive blood culture bottles and colonies. A total of 2381 (93.9%) and 146 (5.8%) of the positive blood cultures were monomicrobial and polymicrobial, respectively. And 1330 (55.9%), 922 (38.7%), 60 (2.5%), 36 (1.5%) and 13 of the isolates were gram-positive cocci (GPC), gram-negative bacilli (GNB), anaerobic bacteria, gram-positive bacilli (GPB) and yeast respectively. Concordance between both methods was 81.7% (76.7% of GPC, 90% of GNB, 74.2% of anaerobic bacteria and 33.3% of GPB) in monomicrobial cultures. Eighty eight per cent of the polymicrobial cultures were identified correctly in at least one of the two bacteria. The results of the present study show that this fast, MALDI-TOF MS based method allows microbial identification directly from positive blood culture in a short time, with a high accuracy, with the exception of gram-positive bacilli.

Resumo A espectrometria de massa (MALDI-TOF MS) permite a identificação de microorganismos diretamente das colônias em minutos. Nesse estudo, foi desenvolvido um protocolo reduzido para identificar microrganismos diretamente das garrafas de hemoculturas positivas em 30 minutos com alta sensibilidade e especificidade, utilizando MALDI-TOF. Um total de 2535 hemoculturas positivas foram relatadas -o método direto de MALDI-TOF MS, a partir de uma alíquota de sangue dos vidros e o método de colônia, a partir das culturas desenvolvidas em meios sólidos. Do total de hemoculturas positivas incluídas neste estudo, 2.381 (93,9%) eram monomicrobianas e 146 (5,8%) eram polimicrobianas. Mil trezentos e trinta (55,9%) dos isolados corresponderam a cocos gram-positivos, 922 (38,7%) bacilos gram-negativos, 60 (2,5%) anaeróbios, 36 (1,5%) bacilos gram-positivos e 13 leveduras. A concordância geral entre os dois métodos foi de 81,7% em nivel de especie (90,0% para bacilos gram-negativos, 76,7% para cocos gram-positivos e 33,3% para bacilos gram-positivos). Pelo menos um germe foi identificado em 88% dos vidros positivos com desenvolvimento polimicrobiano. Os resultados do presente estudo demonstraram que o protocolo baseado em MALDI-TOF MS permite a identificação microbiana diretamente de hemoculturas positivas em um curto espaço de tempo, com alta precisão, com exceção de bacilos gram-positivos.

Clinical Usefulness of Bronchoalveolar Lavage in the Management of Pulmonary Infiltrates in Adults with Hematological Malignancies and Stem Cell Transplantation.

INTRODUCTION: Pulmonary complications are frequent in patients with hematologic malignancies and stem cell transplantation. Regardless of the microbiological usefulness of bronchoalveolar lavage (BAL), little information exists on both its benefits as a guide for therapeutic decisions and its impact on patients' clinical outcome. METHODS: A prospective observational single-center study was performed between July 2011 and July 2016. Consecutive episodes of pulmonary infiltrates were analyzed in subjects over 18 years of age who presented hematologic malignancies and underwent chemotherapy or stem cell transplantation. RESULTS: Ninety-six episodes of pulmonary infiltrates were analyzed. Acute leukemia was the most frequent underlying condition. Thirty-seven patients (38.5%) received a stem cell transplant. Sixty-one (62.9%) were neutropenic at the moment of inclusion in the study. A definitive etiologic diagnosis was obtained in 41 cases (42.7%), where infection accounted for the vast majority of cases (33 cases, 80.5%). Definitive diagnosis was reached by non-invasive methods in 13 cases (13.5%). BAL was performed in 47 cases and led to a diagnosis in 40.4% of the cases. BAL results led to therapeutic changes in 27 cases (57.4%), including the addition of new antimicrobials to empiric treatments in 10. Regarding BAL's safety, two patients experienced minor adverse events and one a severe adverse event; no procedure-related deaths were observed. CONCLUSIONS: Infection was the leading cause of pulmonary infiltrates in patients with hematologic malignancies and stem cell transplantation. BAL was a useful decision-making diagnostic tool, with minor adverse events.

Fungemia following Saccharomyces cerevisiae var. boulardii probiotic treatment in an elderly patient / Fungemia posterior al tratamiento con Saccharomyces cerevisiae var. boulardii como probiótico en una paciente anosa

Abstract The yeast Saccharomyces cerevisiae var. boulardii is a biotherapeutic agent used for the prevention and treatment of several gastrointestinal diseases. We report a case of fungemia in a patient suffering from Clostridium difficile-associated diarrhea and treated with metronidazole and a probiotic containing S. cerevisiae var. boulardii. The yeasts isolated from the blood culture and capsules were identified by MALDI-TOF MS and API ID 32 C as S. cerevisiae, and showed the same appearance and color on CHROMAgar Candida. Treatment with fluconazole 400mg/day was initiated and the probiotic was stopped. The patient was discharged from hospital in good condition and was referred to a rehabilitation center. We suggest that the potential benefit of S. cerevisiae var. boulardii should be accurately evaluated, especially in elderly patients. Moreover, all physicians should be trained in the use of probiotic agents and enquire whether the use probiotics was included in the patients'medical histories. © 2019 Asociación Argentina de Microbiología. Published by Elsevier España, S.L.U. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Resumen Saccharomyces cerevisiae var. boulardii es un agente bioterapéutico usado en la prevención y el tratamiento de varias enfermedades gastrointestinales. Informamos de un caso de fungemia en una paciente con diarrea asociada a Clostridium difficile, y tratada con metron-idazol y un probiótico que contenía S. cerevisiae var. boulardii. Las levaduras aisladas a partir del hemocultivo y del contenido de las cápsulas tomadas por la paciente se identificaron como S. cerevisiae mediante MALDI-TOF MS y API® ID 32C, las colonias mostraron el mismo color y aspecto en el medio CHROMAgar™ Candida. Se instauró un tratamiento con fluconazol 400mg/día y se suspendió el probiótico. La paciente fue dada de alta del hospital en buenas condiciones, y remitida a un centro de rehabilitación. Sugerimos que el beneficio potencial del uso de S. cerevisiae var. boulardii debe ser evaluado en cada paciente, especialmente en personas añosas. El uso de probióticos debería incluirse en los interrogatorios orientados al diagnóstico y formar parte de la historia clínica. © 2019 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. Este es un artículo Open Access bajo la licencia CC BY-NC-ND (https://creativecommons.org/licenses/by-nc-nd/4.0/).

Fungemia following Saccharomyces cerevisiae var. boulardii probiotic treatment in an elderly patient.

The yeast Saccharomyces cerevisiae var. boulardii is a biotherapeutic agent used for the prevention and treatment of several gastrointestinal diseases. We report a case of fungemia in a patient suffering from Clostridiumdifficile-associated diarrhea and treated with metronidazole and a probiotic containing S. cerevisiae var. boulardii. The yeasts isolated from the blood culture and capsules were identified by MALDI-TOF MS and API ID 32 C as S. cerevisiae, and showed the same appearance and color on CHROMAgar Candida. Treatment with fluconazole 400mg/day was initiated and the probiotic was stopped. The patient was discharged from hospital in good condition and was referred to a rehabilitation center. We suggest that the potential benefit of S. cerevisiae var. boulardii should be accurately evaluated, especially in elderly patients. Moreover, all physicians should be trained in the use of probiotic agents and enquire whether the use probiotics was included in the patients'medical histories.

Development and validation of an extended database for yeast identification by MALDI-TOF MS in Argentina.

Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has revolutionized the identification of microorganisms in clinical laboratories because it is rapid, relatively simple to use, accurate, and can be used for a wide number of microorganisms. Several studies have demonstrated the utility of this technique in the identification of yeasts; however, its performance is usually improved by the extension of the database. Here we developed an in-house database of 143 strains belonging to 42 yeast species in the MALDI Biotyper platform, and we validated the extended database with 388 regional strains and 15 reference strains belonging to 55 yeast species. We also performed an intra- and interlaboratory study to assess reproducibility and analyzed the use of the cutoff values of 1.700 and 2.000 to correctly identify at species level. The creation of an in-house database that extended the manufacturer's database was successful in view of no incorrect identification was introduced. The best performance was observed by using the extended database and a cutoff value of 1.700 with a sensitivity of .94 and specificity of .96. A reproducibility study showed utility to detect deviations and could be used for external quality control. The extended database was able to differentiate closely related species and it has potential in distinguishing the molecular genotypes of Cryptococcus neoformans and Cryptococcus gattii.

Identificación de levaduras del género Candida: los métodos convencionales frente a MALDI-TOF MS / Identification of Candida yeasts: Conventional methods and MALDI-TOF MS

Antecedentes: Las infecciones fúngicas invasivas han ido aumentando y las levaduras del género Candida son la principal causa de las mismas. Las especies distintas de Candida albicans son cada vez más frecuentes y algunas pueden presentar patrones variables de sensibilidad a los antimicóticos, por lo que es importante la correcta identificación de la especie. Los métodos de identificación convencionales con los que cuentan la mayoría de los laboratorios pueden presentar inconvenientes. La espectrometría de masas (MALDI-TOF MS) surgió como una alternativa a los mismos. Objetivos: Evaluar la concordancia de los resultados de identificación de diferentes especies de Candida mediante dostécnicas: una convencional (galerías API) y MALDI-TOF MS. Métodos: Se analizaron las siguientes especies y número de aislamientos: Candida parapsilosis (28), Candida glabrata (34), Candida krusei (24), Candida tropicalis (45), Candida guilliermondii (30), C. albicans (28), Candida dubliniensis (6), Candida kefyr (1) y Candida lipolytica (1) del cepario de RMCABA; también se utilizaron las cepas C. parapsilosis 22019, C. glabrata 90030, C. krusei 6258 y C. albicans 68548, pertenecientes a la American Type Culture Collection (ATCC). Las discrepancias en la identificación se resolvieron mediante genotipificación. Resultados y conclusiones: La concordancia directa entre la identificación convencional y MALDI-TOF MS fue del 92,5% (186/201)

Background: Invasive fungal infections are increasing, and Candida yeasts are the main cause. Species other than Candida albicans are becoming more frequent, and some of them may have variable patterns of susceptibility to antifungal agents, making it important to identify them correctly. Conventional identification methods used by most laboratories may present with drawbacks. Mass spectrometry (MALDI-TOF MS) has emerged as an alternative method. Aims: The aim of this study was to evaluate the concordance of the identification, at species level, by conventional methods (API) and MALDI-TOF MS. Methods: The following species and number of isolates were studied: Candida parapsilosis (28), Candida glabrata (34), Candida krusei (24), Candida tropicalis (45), Candida guilliermondii (30), C. albicans (28), Candida dubliniensis (6), Candida kefyr (1), and Candida lipolytica (1) from the strain collection of Autonomous City of Buenos Aires Mycology Network (RMCABA). The strains C. parapsilosis 22019, C. glabrata 90030, C. krusei 6258 and C. albicans 68548 from the American Type Culture Collection (ATCC) were also included. Discrepancies were resolved by genotyping. Results and conclusions: The direct concordance between the conventional identification method and MALDI-TOF MS was 92.5% (186/201)

[Identification of Candida yeasts: Conventional methods and MALDI-TOF MS]. / Identificación de levaduras del género Candida: los métodos convencionales frente a MALDI-TOF MS.

BACKGROUND: Invasive fungal infections are increasing, and Candida yeasts are the main cause. Species other than Candida albicans are becoming more frequent, and some of them may have variable patterns of susceptibility to antifungal agents, making it important to identify them correctly. Conventional identification methods used by most laboratories may present with drawbacks. Mass spectrometry (MALDI-TOF MS) has emerged as an alternative method. AIMS: The aim of this study was to evaluate the concordance of the identification, at species level, by conventional methods (API) and MALDI-TOF MS. METHODS: The following species and number of isolates were studied: Candida parapsilosis (28), Candida glabrata (34), Candida krusei (24), Candida tropicalis (45), Candida guilliermondii (30), C. albicans (28), Candida dubliniensis (6), Candida kefyr (1), and Candida lipolytica (1) from the strain collection of Autonomous City of Buenos Aires Mycology Network (RMCABA). The strains C. parapsilosis 22019, C. glabrata 90030, C. krusei 6258 and C. albicans 68548 from the American Type Culture Collection (ATCC) were also included. Discrepancies were resolved by genotyping. RESULTS AND CONCLUSIONS: The direct concordance between the conventional identification method and MALDI-TOF MS was 92.5% (186/201).

Infecciones urinarias nosocomiales por levaduras. Estudio multicéntrico de 14 hospitales de la red de micología de la Ciudad Autónoma de Buenos Aires / Yeast urinary tract infections. Multicentre study in 14 hospitals belonging to the Buenos Aires City Mycology Network

Antecedentes. Las infecciones del tracto urinario son una complicación en las unidades de cuidados intensivos. Las levaduras ocasionan el 5-12% de dichas infecciones. El valor del hallazgo de las levaduras es controvertido y no hay consenso acerca de qué parámetros son los adecuados para diferenciar entre contaminación, colonización e infección urinaria. Objetivos. Analizar las características epidemiológicas de pacientes con funguria, determinar potenciales puntos de corte en los cultivos para distinguir la infección urinaria de otras situaciones, identificar las especies de levaduras prevalentes y determinar el valor de la segunda muestra de orina. Métodos. Se realizó un estudio multicéntrico en unidades de cuidados intensivos de 14 hospitales. Se procesaron primeras y segundas muestras para urocultivo, se evaluaron la presencia de leucocitos y levaduras en el examen directo, se hizo un recuento de colonias y se identificaron las especies aisladas. Resultados. Hubo crecimiento de levaduras en el 12,2% de las muestras. No hubo correlación entre el número de leucocitos y el de unidades formadoras de colonias de levaduras. El 85% de los pacientes tenían catéteres vesicales. No se observó mayor prevalencia ni en mujeres ni en pacientes adultos mayores de 65 años. Candida albicans fue la especie más frecuente, seguida por Candida tropicalis y, en menor proporción, por Candida parapsilosis y Candida glabrata. En la segunda muestra se corroboró la presencia de la misma especie en el 70% de los casos, y en el 23% de ellos el segundo cultivo fue negativo. Conclusiones. No fue posible determinar un punto de corte en el recuento de colonias que oriente al diagnóstico de infección urinaria. Las dos especies prevalentes fueron C. albicans y C. tropicalis (AU)

Background. Urinary tract infections are a frequent ailment in patients in intensive care units. Candida and other yeasts cause 5-12% of these infections. The value of the finding of any yeast is controversial, and there is no consensus about which parameters are adequate for differentiating urinary infections from colonization or contamination. Aims. To analyse the epidemiological characteristics of patients with funguria, to determine potential cut-off points in cultures (to distinguish an infection from other conditions), to identify the prevalent yeast species, and to determine the value of a second urine sample. Methods. A multicentre study was conducted in intensive care units of 14 hospitals in the Buenos Aires City Mycology Network. The first and second samples of urine from every patient were cultured. The presence of white cells and yeasts in direct examination, colony counts, and the identification of the isolated species, were evaluated. Results. Yeasts grew in 12.2% of the samples. There was no statistical correlation between the number of white cells and the fungal colony-forming units. Eighty five percent of the patients had indwelling catheters. Funguria was not prevalent in women or in patients over the age of 65. Candida albicans, followed by Candida tropicalis, were the most frequently isolated yeasts. Candida parapsilosis and Candida glabrata appeared less frequently. The same species were isolated in 70% of second samples, and in 23% of the cases the second culture was negative. Conclusions. It was not possible to determine a useful cut-off point for colony counts to help in the diagnosis of urinary infections. As in other publications, C. albicans, followed by C. tropicalis, were the most prevalent species (AU)

[Yeast urinary tract infections. Multicentre study in 14 hospitals belonging to the Buenos Aires City Mycology Network]. / Infecciones urinarias nosocomiales por levaduras. Estudio multicéntrico de 14 hospitales de la red de micología de la Ciudad Autónoma de Buenos Aires.

BACKGROUND: Urinary tract infections are a frequent ailment in patients in intensive care units. Candida and other yeasts cause 5-12% of these infections. The value of the finding of any yeast is controversial, and there is no consensus about which parameters are adequate for differentiating urinary infections from colonization or contamination. AIMS: To analyse the epidemiological characteristics of patients with funguria, to determine potential cut-off points in cultures (to distinguish an infection from other conditions), to identify the prevalent yeast species, and to determine the value of a second urine sample. METHODS: A multicentre study was conducted in intensive care units of 14 hospitals in the Buenos Aires City Mycology Network. The first and second samples of urine from every patient were cultured. The presence of white cells and yeasts in direct examination, colony counts, and the identification of the isolated species, were evaluated. RESULTS: Yeasts grew in 12.2% of the samples. There was no statistical correlation between the number of white cells and the fungal colony-forming units. Eighty five percent of the patients had indwelling catheters. Funguria was not prevalent in women or in patients over the age of 65. Candida albicans, followed by Candida tropicalis, were the most frequently isolated yeasts. Candida parapsilosis and Candida glabrata appeared less frequently. The same species were isolated in 70% of second samples, and in 23% of the cases the second culture was negative. CONCLUSIONS: It was not possible to determine a useful cut-off point for colony counts to help in the diagnosis of urinary infections. As in other publications, C. albicans, followed by C. tropicalis, were the most prevalent species.

Saksenaea erythrospora infection following a serious sailing accident.

Saksenaea erythrospora is a species of the order Mucorales recently described and reported as a cause of human mucormycosis. We report a case of S. erythrospora in a man involved in a serious sailing accident causing deep skin and soft tissue contamination with soil and water. Direct microscopic examination of the clinical sample with Giemsa stains showed hyaline and non-septate hyphae belonging to the order Mucorales. Fungal identification was performed by culture of biopsy material on SDA, and identification of species by floating an agar block containing the fungus in a nutritionally deficient medium consisting of sterile distilled water supplemented with 0.05 % yeast extract; and by sequencing the ITS region of the rDNA. This is the first report to our knowledge of infection with S. erythrospora in Argentina, confirming the presence of this fungus in this country.

Emergence of Pseudomonas aeruginosa with KPC-type carbapenemase in a teaching hospital: an 8-year study.

An outbreak of Klebsiella pneumoniae carbapenamase (KPC)-producing K. pneumoniae occurred at our institution. Multiresistant Pseudomonas aeruginosa could have acquired this transmissible resistance mechanism, going unnoticed because its phenotypic detection in this species is difficult. We compared P. aeruginosa isolates obtained before and after the KPC-producing K. pneumoniae outbreak. No bla(KPC) genes were detected in the isolates obtained before the outbreak, whereas 33/76 (43%) of the isolates obtained after the outbreak harboured the bla(KPC) gene. P. aeruginosa may thus become a reservoir of this transmissible resistance mechanism. It is very important to understand the epidemiology of these multiresistant isolates, in order to achieve early implementation of adequate control measures to contain and reduce their dissemination in the hospital environment.

Onicomicosis: estudio multicéntrico clínico, epidemiológico y micológico / Onychomycosis: multicentre epidemiological, clinical and mycological study

Antecedentes. Las onicomicosis representan aproximadamente el 50% de las onicopatías, pueden ser causadas por dermatofitos, levaduras u hongos filamentosos no dermatofitos. Objetivos y metodología. Se realizó un estudio multicéntrico para conocer la prevalencia de onicomicosis, los agentes causales y las formas clínicas más frecuentes. Se evaluaron todas las muestras de uñas de manos y pies durante el período de un año en 9 centros asistenciales. Resultados. Se procesaron 5.961 muestras, el 82,3% correspondieron a uñas de pies y el 17,7% a uñas de manos. La edad promedio de los pacientes fue 49,7 años y el 66% perteneció al sexo femenino. Los exámenes directos fueron positivos en el 61% de los casos. En adultos, las uñas de los pies presentaron un 61,2% de resultados positivos en el examen directo, y los cultivos fueron positivos en un 43,7%. Los hongos predominantes fueron los dermatofitos (82,8%) y la forma clínica más frecuente fue la distal subungueal. En uñas de manos la positividad del examen directo fue del 59,8% y los cultivos fueron positivos en un 52,9%; los hongos predominantes fueron de tipo levaduriforme y la forma clínica más frecuente fue la onicolisis. Conclusiones. Se encontró un 61% de positividad en el examen directo, valor superior al de otras investigaciones. En las uñas de los pies prevalecieron los dermatofitos en ambos sexos, y en uñas de manos las levaduras, en el sexo femenino, y dermatofitos, en el masculino. El 4,8% de los aislamientos de uñas de pies y el 2,05% de los de uñas de manos fueron de hongos filamentosos no dermatofíticos(AU)

Background. Onychomycosis accounts for up to 50% of all nail disorders. They can be caused by: yeasts, dermatophytes and non-dermatophyte moulds. Objectives and methods. A multicentre study designed to determine the prevalence, mycological test results, aetiological agents, and clinical presentation of onychomycosis was carried out. All fingernail and toenail samples taken during a one year period at 9 diagnostic centres were included. Results. A total of 5,961 samples were analysed, of which 82.3% were from toenails and 17.7% from fingernails. The mean age of the patients was 49.7 years, and 66% were females. Direct microscopic examination was positive in 61% of the samples. In adults, 61.2% of toenails were positive using potassium hydroxide (KOH), and 43.7% were positive in cultures. The prevailing aetiological agents belong to the dermatophyte group (82.8%), and distal subungual was the most common clinical form. In fingernails, direct examination showed 59.8% positive samples, and cultures were positive in 52.9%. The prevailing agents were yeasts belonging to Candida species, and onycholysis was the most common lesion. Conclusions. Direct mycological examinations were positive in 61%, a higher value than that found in other series. Dermatophytes were prevalent in toenails of both sexes, and in finger nails yeast were prevalent in females, and dermatophytes in males. Non-dermatophyte moulds corresponded to 4.8% of toenail and 2.05% of fingernails isolates(AU)

[Onychomycosis: multicentre epidemiological, clinical and mycological study]. / Onicomicosis: estudio multicéntrico clínico, epidemiológico y micológico.

BACKGROUND: Onychomycosis accounts for up to 50% of all nail disorders. They can be caused by: yeasts, dermatophytes and non-dermatophyte moulds. OBJECTIVES AND METHODS: A multicentre study designed to determine the prevalence, mycological test results, aetiological agents, and clinical presentation of onychomycosis was carried out. All fingernail and toenail samples taken during a one year period at 9 diagnostic centres were included. RESULTS: A total of 5,961 samples were analysed, of which 82.3% were from toenails and 17.7% from fingernails. The mean age of the patients was 49.7 years, and 66% were females. Direct microscopic examination was positive in 61% of the samples. In adults, 61.2% of toenails were positive using potassium hydroxide (KOH), and 43.7% were positive in cultures. The prevailing aetiological agents belong to the dermatophyte group (82.8%), and distal subungual was the most common clinical form. In fingernails, direct examination showed 59.8% positive samples, and cultures were positive in 52.9%. The prevailing agents were yeasts belonging to Candida species, and onycholysis was the most common lesion. CONCLUSIONS: Direct mycological examinations were positive in 61%, a higher value than that found in other series. Dermatophytes were prevalent in toenails of both sexes, and in finger nails yeast were prevalent in females, and dermatophytes in males. Non-dermatophyte moulds corresponded to 4.8% of toenail and 2.05% of fingernails isolates.

Phenotypic and genotypic characterization of Aspergillus lentulus and Aspergillus fumigatus isolates in a patient with probable invasive aspergillosis.

Characteristic morphological and phylogenetic analyses demonstrated the presence of Aspergillus fumigatus and Aspergillus lentulus as the aetiological agents in a case of probable invasive aspergillosis (IA). This is believed to be the first report of an A. lentulus strain isolated from a patient with probable IA in Argentina.