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.

Study of the genetic diversity of Moraxella spp. isolates obtained from corneal abscesses / Estudio de la diversidad genética de aislamientos de Moraxella spp. a partir de abscesos corneales

Abstract This is the first study of the genetic diversity of Moraxella spp. Isolates were detected in an Eye Hospital in the City of Buenos Aires. Due to the high frequency of Moraxella spp. observed in corneal abscesses, we decided to validate their identification at the species level, determine their drug susceptibility and perform molecular subtyping. Seventeen (17) isolates obtained from corneal abscesses were evaluated. The identification was carried out using a combination of biochemical tests and MALDI-TOF mass spectrometry. Of these isolates, 88.2% were identified as Moraxella lacunata, and 11.8% as Moraxella nonliquefaciens. Molecular subtyping was performed using the pulsed-field gel electrophoresis (PFGE) technique. All isolates were typable and thirteen digestion patterns were identified. Based on the obtained results, the PFGE technique using the SmaI enzyme can be used for epidemiological studies of strains of these species.

Resumen En este trabajo se presenta el primer estudio de diversidad genética de aislamientos de Moraxella spp. detectados en un hospital de oftalmología de la Ciudad Autónoma de Buenos Aires. Debido a la observación de una elevada frecuencia de Moraxella spp. en abscesos corneales, se decidió confirmar su identificación a nivel de especie, conocer su sensibilidad y realizar la subtipificación molecular. Se analizaron 17 aislamientos provenientes de abscesos corneales. La identificación se realizó mediante una combinación de pruebas bioquímicas y espectrometría de masas, MALDI-TOF MS. El 88,2% fueron identificados como Moraxella lacunata y el 11,8% como Moraxella nonliquefaciens. La subtipificación molecular se realizó por la técnica de electroforesis en gel de campo pulsado (PFGE). Todos los aislamientos fueron tipificables y se identificaron 13 patrones de digestión. Nuestros resultados muestran que la técnica de PFGE con la enzima SmaI es útil para hacer estudios epidemiológicos en cepas de estas especies.

Study of the genetic diversity of Moraxella spp. isolates obtained from corneal abscesses.

This is the first study of the genetic diversity of Moraxella spp. Isolates were detected in an Eye Hospital in the City of Buenos Aires. Due to the high frequency of Moraxella spp. observed in corneal abscesses, we decided to validate their identification at the species level, determine their drug susceptibility and perform molecular subtyping. Seventeen (17) isolates obtained from corneal abscesses were evaluated. The identification was carried out using a combination of biochemical tests and MALDI-TOF mass spectrometry. Of these isolates, 88.2% were identified as Moraxella lacunata, and 11.8% as Moraxella nonliquefaciens. Molecular subtyping was performed using the pulsed-field gel electrophoresis (PFGE) technique. All isolates were typable and thirteen digestion patterns were identified. Based on the obtained results, the PFGE technique using the SmaI enzyme can be used for epidemiological studies of strains of these species.

Comparison of the identification results of Candida species obtained by BD PhoenixT and Maldi-TOF (Bruker Microflex LT Biotyper 3.1) / Comparación de los resultados de identificación de especies del género Candida obtenidos por BD PhoenixT y Maldi-TOF (Bruker Microflex LT Biotyper 3.1)

In patients with invasive fungal infections, the accurate and rapid identification of the genus Candida is of utmost importance since antimycotic sensitivity is closely related to the species. The aim of the present study was to compare the identification results of species of the genus Candida obtained by BD PhoenixT (Becton Dickinson -#91;BD-#93;) and Maldi-TOF MS (Bruker Microflex LT Biotyper 3.1). A total of 192 isolates from the strain collection belonging to the Mycology Network of the Autonomous City of Buenos Aires, Argentina, were analyzed. The observed concordance was 95%. Only 10 strains (5%) were not correctly identified by the BD PhoenixT system. The average identification time with the Yeast ID panels was 8h 22 min. The BD PhoenixT system proved to be a simple, reliable and effective method for identifying the main species of the genus Candida.

En pacientes con infecciones fúngicas invasoras, la identificación certera y rápida de las especies del género Candida es de suma importancia, ya que la sensibilidad a los antifúngicos está íntimamente relacionada con la especie. El objetivo del presente estudio fue comparar los resultados de identificación de especies del género Candida obtenidos con el equipo comercial BD PhoenixT (Becton Dickinson -#91;BD-#93;) y con la técnica de Maldi-TOF MS (Bruker Microflex LT Biotyper 3.1.) Se analizaron 192 aislamientos provenientes del cepario perteneciente a la Red deMicología de la Ciudad Autónoma de Buenos Aires, Argentina. La concordancia observada fue del 95%. Solo 10 cepas (5%) no fueron identificadas correctamente por el sistema BD PhoenixT. El tiempo promedio de identificación con los paneles Yeast ID fue de 8 h 22 min. El sistema BD PhoenixT demostró ser un método simple, confiable y efectivo para la identificación de las principales especies del género Candida.

Comparison of the identification results of Candida species obtained by BD Phoenix™ and Maldi-TOF (Bruker Microflex LT Biotyper 3.1).

In patients with invasive fungal infections, the accurate and rapid identification of the genus Candida is of utmost importance since antimycotic sensitivity is closely related to the species. The aim of the present study was to compare the identification results of species of the genus Candida obtained by BD Phoenix™ (Becton Dickinson [BD]) and Maldi-TOF MS (Bruker Microflex LT Biotyper 3.1). A total of 192 isolates from the strain collection belonging to the Mycology Network of the Autonomous City of Buenos Aires, Argentina, were analyzed. The observed concordance was 95%. Only 10 strains (5%) were not correctly identified by the BD Phoenix™ system. The average identification time with the Yeast ID panels was 8h 22min. The BD Phoenix™ system proved to be a simple, reliable and effective method for identifying the main species of the genus Candida.

Keratitis caused by moulds in Santa Lucía Ophthalmology Hospital in Buenos Aires, Argentina / Queratitis causada por hongos miceliares en el Hospital Oftalmológico Santa Lucía de Buenos Aires, Argentina(AU)

Background. Mycotic keratitis by moulds (MKM) is an important cause for corneal blindness and usually carries an unfavorable prognosis. Aims. This study describes the risk factors and demographic and microbiological features of all MKM cases in Santa Lucía Ophthalmology Hospital during a period of 6 years. Methods. A prospective study was performed for all MKM cases diagnosed between October 2007 and September 2013. Results. Among 157 diagnosed cases, direct microscopic examination and culture were positive in 97 and 96% of the cases respectively. MKM represents 17% of all microbiologically confirmed corneal abscesses. No significant differences were detected in annual MKM frequencies across the study period, suggesting that MKM incidence remains constant over time. A male-to-female ratio was observed (2.8:1); the most affected age groups ranged from 31 to 40 years old (males) and 61-70 years old (females). The most frequent predisposing factor was trauma (40%) followed by the use of contact lenses (9%), herpetic abscesses (5%) and diabetes (4%). The predominant genera were Fusarium (66%), Aspergillus (10%), Curvularia (6%) and Alternaria (4%). The most frequent agent was Fusarium solani species complex (52%). More than two-thirds of the cases were produced by only 3 species or complexes. However, at least 29 different species were detected in the remaining cases. This is the first report of Pholiota sp. as causative agent of human MKM. Conclusions. Argentina lacks extensive epidemiological and clinical data on MKM. This six-year study performed in Argentina is a first step leading to a better understanding of MKM epidemiology in our country (AU)

Antecedentes. La queratitis micótica causada por hongos miceliares (MKM) es una causa importante de ceguera corneal y presenta un pronóstico desfavorable. Objetivos. Describir los factores de riesgo y las características demográficas y microbiológicas de las MKM diagnosticadas en el Hospital Oftalmológico Santa Lucía durante 6 años. Métodos. Se llevó a cabo un estudio prospectivo de todos los casos de MKM diagnosticados entre octubre de 2007 y septiembre de 2013. Resultados. Se diagnosticaron 157 casos de MKM: un 97% con examen directo positivo y un 96% con cultivo positivo. Las MKM representaron el 17% de todos los abscesos corneales microbiológicamente confirmados. No se encontraron diferencias significativas en esta proporción durante los seis años de estudio, lo que demuestra que la incidencia permaneció constante. La proporción varones:mujeres fue 2,8:1; las edades más afectadas fueron 31-40 años en los varones y 61-70 años en las mujeres. El factor predisponente más común fue el traumatismo (40%), seguido del uso de lentes de contacto (9%), abscesos herpéticos (5%) y diabetes (4%). Los géneros predominantes fueron Fusarium (66%), Aspergillus (10%), Curvularia (6%) y Alternaria (4%). Los agentes más frecuentes pertenecían al complejo de especies Fusarium solani (52%). Más de dos tercios de los casos fueron causados únicamente por 3 especies, o complejos de especies, pero en los restantes se detectaron al menos otras 28 especies. Este es el primer informe referente a Pholiota sp. como agente causal de MKM humana. Conclusiones. Argentina carece de datos epidemiológicos y clínicos consolidados sobre MKM. Este estudio contribuye a una mejor comprensión de la epidemiología de esta enfermedad en este país (AU)

Keratitis caused by moulds in Santa Lucía Ophthalmology Hospital in Buenos Aires, Argentina.

BACKGROUND: Mycotic keratitis by moulds (MKM) is an important cause for corneal blindness and usually carries an unfavorable prognosis. AIMS: This study describes the risk factors and demographic and microbiological features of all MKM cases in Santa Lucía Ophthalmology Hospital during a period of 6 years. METHODS: A prospective study was performed for all MKM cases diagnosed between October 2007 and September 2013. RESULTS: Among 157 diagnosed cases, direct microscopic examination and culture were positive in 97 and 96% of the cases respectively. MKM represents 17% of all microbiologically confirmed corneal abscesses. No significant differences were detected in annual MKM frequencies across the study period, suggesting that MKM incidence remains constant over time. A male-to-female ratio was observed (2.8:1); the most affected age groups ranged from 31 to 40 years old (males) and 61-70 years old (females). The most frequent predisposing factor was trauma (40%) followed by the use of contact lenses (9%), herpetic abscesses (5%) and diabetes (4%). The predominant genera were Fusarium (66%), Aspergillus (10%), Curvularia (6%) and Alternaria (4%). The most frequent agent was Fusarium solani species complex (52%). More than two-thirds of the cases were produced by only 3 species or complexes. However, at least 29 different species were detected in the remaining cases. This is the first report of Pholiota sp. as causative agent of human MKM. CONCLUSIONS: Argentina lacks extensive epidemiological and clinical data on MKM. This six-year study performed in Argentina is a first step leading to a better understanding of MKM epidemiology in our country.

Estudio comparativo de los gérmenes más frecuentes aislados en abscesos corneales y su sensibilidad / Compartive study of the germs more frequently isolated in abscesses and their sensibility

Objetivo: estudiar la prevalencia de microorganismos y su sensibilidad en abscesos de córnea para que la terapia sea optimizada y dirigida específicamente hacia el microorganismo aislado.Asimismo, evaluar la estabilidad en la prevalencia.Métodos: el presente estudio se realiza en forma retrospectiva (junio 2001-junio 2002-julio 2003) sobre el total de 460 casos de abscesos de córnea sembrados en sus inicios en los diferentes Servicios del Hospital Santa Lucía con su posterior aislamiento, tipificación y sensibilidad en el Area de Bacteriología.Resultados: los gérmenes más frecuentes aislados en los dos períodos fueron: Estafilococos, Pseudomonas, Hongos, Neumococo, Enterobacterias, otros. No se observaron cambios significativos en cuanto a prevalencia, salvo Streptococus pneumoniae, donde el número de casos fue mucho mayor en el período 2002-2003(aumento del 90 porciento). Los gérmenes aislados fueron altamente sensibles a los antimicrobianos ensayados.

Estudio comparativo de los gérmenes más frecuentes aislados en abscesos corneales y su sensibilidad / Compartive study of the germs more frequently isolated in abscesses and their sensibility

Objetivo: estudiar la prevalencia de microorganismos y su sensibilidad en abscesos de córnea para que la terapia sea optimizada y dirigida específicamente hacia el microorganismo aislado.Asimismo, evaluar la estabilidad en la prevalencia.Métodos: el presente estudio se realiza en forma retrospectiva (junio 2001-junio 2002-julio 2003) sobre el total de 460 casos de abscesos de córnea sembrados en sus inicios en los diferentes Servicios del Hospital Santa Lucía con su posterior aislamiento, tipificación y sensibilidad en el Area de Bacteriología.Resultados: los gérmenes más frecuentes aislados en los dos períodos fueron: Estafilococos, Pseudomonas, Hongos, Neumococo, Enterobacterias, otros. No se observaron cambios significativos en cuanto a prevalencia, salvo Streptococus pneumoniae, donde el número de casos fue mucho mayor en el período 2002-2003(aumento del 90 porciento). Los gérmenes aislados fueron altamente sensibles a los antimicrobianos ensayados.(AU)