Sertaconazole antifungal profile determined by a microdilution method versus nine topical substances against dermatophyte fungi.

Antifungal activity and in vitro inhibition time for sertaconazole (STZ) and 9 other topical drugs, namely amorolfine, bifonazole, clotrimazole, econazole, ketoconazole, miconazole, oxiconazole, terbinafine, and tioconazole were determined against 124 clinical isolates of dermatophyte (12 species) fungi by the microdilution method in a liquid medium and the measurement of optical density. STZ's antifungal activity was not always affected by the tested dermatophyte genus, as was the case with the remaining antifungals. In vitro antifungal activity was at the same level for all the studied azole derivatives, but, in terms of partial inhibitory concentrations, STZ starts its in vitro inhibitory activity in a shorter time than the other tested substances, particularly in those incubation periods when the growth of the dermatophyte fungi was more developed.

Antifungal activity of posaconazole against Candida spp. and non-Candida clinical yeasts isolates.

The in vitro antifungal activity of posaconazole was tested against 315 yeast clinical isolates and 11 ATCC reference strains by means an agar diffusion method (Neosensitabs, Rosco,Denmark) based in CLSI M44-A2 document. Posaconazole activity was excellent against Cryptococcus and Rhodotorula species studied and showed very good activity against most species of Candida tested. A total of 13 clinical isolates (4.1%) were resistant: Candida albicans (n=5), Candida glabrata (n=5), Candida tropicalis (n=1), Geotrichum australiensis (n=1) and Geotrichum capitatum (n=1). Our results suggest posaconazole is an effective antifungal agent against the most clinically important yeasts species (92.7% of susceptibility). Agar diffusion method provides good conditions for the posaconazole susceptibility study in the routine laboratory.

Aplicación del aprendizaje basado en problemas para la enseñanza de la microbiología en estudiantes de Medicina / Application of the problem-based learning for the Microbiology teaching among Medicine students

El aprendizaje basado en problemas (ABP) es uno de los métodos de enseñanza-aprendizaje frecuentemente utilizado en las instituciones de educación superior en los últimos años, pero su aplicación aún no abarca todos los ámbitos de la Medicina. Objetivo. Evaluar el método del ABP en la enseñanza de la microbiología en comparación con los métodos tradicionales basados en talleres y seminarios. Sujetos y métodos. El estudio se realizó en la Cátedra de Microbiología, Parasitología e Inmunología de la Facultad de Medicina de la Universidad Nacional del Nordeste, Corrientes, Argentina. El total de alumnos de la asignatura se dividieron en un grupo control (a quienes se aplicó la enseñanza tradicional) y un grupo experimental(con quienes se trabajó con técnica de ABP). Los alumnos de ambos grupos fueron evaluados individualmente a través de un cuestionario de opciones múltiples y grupalmente mediante una encuesta de opinión. Resultados y conclusiones. No se observó diferencia significativa en cuanto a los conocimientos adquiridos en ambos grupos. El grupo de ABP mostró mayor compromiso y motivación para desarrollar la actividad asignada, pero esa diferencia no fue estadísticamente significativa (AU)

The problem-based learning (PBL) is one of the teaching-learning methods more used in the institutions of higher education in recent years, but its application still does not cover all areas of Medicine. Aim. To compare the PBL with the traditional method based in seminars and workshops in the Microbiology teaching. Subjects and methods. The study was carried out in the subject of Microbiology, Immunology and Parasitology, Faculty of Medicine, Universidad Nacional del Nordeste, Corrientes, Argentina. Students were divided into a control group (in which the traditional teaching methods were applied) and an experimental group (in which the PB Lwas applied). Students were individually evaluated by a multiple choice questionnaire. One opinion survey was applied in groups. Results and conclusions. No significant difference was observed between the groups in terms of knowledge gained. The PBL group showed greater commitment and motivation to develop the assigned activity, although without statistically significant differences (AU)

[Paracoccidioidomycosis in Formosa province (Argentina)]. / Paracoccidioidomicosis en la Provincia de Formosa, Argentina.

Patients with paracoccidioidomycosis (PCM) compatible symptoms who attended Hospital Central de Formosa, were studied during 2 years. Three hundred and thirty five patients were selected, 264 male and 71 female, ages were between 25 and 79 years old. Twenty four patients were diagnosed, the prevalence observed was 7.16%. There was only one female positive case. Most patients (83%) had smoked for more than 10 years, 96% came from a rural area and 63% was alcoholic. Also a case of neuroparacoccidioidomycosis and a juvenile-type PCM case were detected. Specimens of mucocutaneous lesions were 100% positives. Immunodiffusion (IDGA) allowed the diagnostic in 22/249 patients. PCM and others infectious diseases with similar clinical manifestations coexist in Formosa province, for this reason differential diagnostic must be done.

Paracoccidioidomicosis en la Provincia de Formosa, Argentina / Paracoccidioidomycosis in Formosa province (Argentina)

Durante 2 años, en un estudio de corte trasversal, se estudiaron los pacientes con síntomas compatibles con paracoccidioidomicosis (PCM) que concurrieron al Hospital Central de Formosa. Se seleccionaron 335 enfermos, de los cuales 264 eran varones y 71 mujeres, con edades comprendidas entre los 25 y los 79 años. Se hizo diagnóstico de PCM en 24 pacientes, obteniéndose una prevalencia de 7,16%. Hubo un solo caso femenino. La mayoría (83%) de los pacientes había consumido tabaco por un tiempo mayor a 10 años, el 96% pertenecía al área rural y el 63% de ellos refería una ingesta elevada de alcohol. Se detectaron también un caso de PCM infanto-juvenil y uno de neuroparacoccidioidomicosis. El 100% de las muestras de lesiones muco-cutáneas de pacientes con PCM estudiadas fue positivo. El estudio serológico por inmunodifusión en gel de agar (IDGA) permitió el diagnóstico en 22/249 pacientes estudiados. La PCM es endémica en la provincia de Formosa donde coexiste con otras afecciones con manifestaciones semejantes, por lo que se debe realizar siempre el diagnóstico diferencial.

Patients with paracoccidioidomycosis (PCM) compatible symptoms who attended Hospital Central de Formosa, were studied during 2 years. Three hundred and thirty five patients were selected, 264 male and 71 female, ages were between 25 and 79 years old. Twenty four patients were diagnosed, the prevalence observed was 7.16%. There was only one female positive case. Most patients (83%) had smoked for more than 10 years, 96% came from a rural area and 63% was alcoholic. Also a case of neuroparacoccidioidomycosis and a juvenile-type PCM case were detected. Specimens of mucocutaneous lesions were 100% positives. Immunodiffusion (IDGA) allowed the diagnostic in 22/249 patients. PCM and others infectious diseases with similar clinical manifestations coexist in Formosa province, for this reason differential diagnostic must be done.

Activity of caspofungin and voriconazole against clinical isolates of Candida and other medically important yeasts by the CLSI M-44A disk diffusion method with Neo-Sensitabs tablets.

In vitro activity of caspofungin and voriconazole against 184 clinical isolates of Candida and other medically important yeasts in comparison with that of fluconazole, ketoconazole, itraconazole and amphotericin B was determined by using a disk diffusion method (Neo-Sensitabs) standardized according to the recommendations of the CLSI documents M44-A and M44-S1 (same medium: Mueller-Hinton plus methylene blue; inoculum and minimal inhibitory concentration/zone breakpoints). Seventy-two percent of clinical isolates were susceptible to caspofungin, 23.6% showed an intermediate susceptibility (most of them were Candida parapsilosis) and 4.3% were resistant (values for Candida spp. were 71.2, 23.8 and 5%, respectively). For voriconazole, 96.7% of clinical isolates were susceptible and 3.3% were resistant (Candida spp.: 96 and 3.8%, respectively). Both caspofungin and voriconazole showed high activity against a wide variety of clinically important yeasts.

[Association of paracoccidioidomycosis with different pulmonary pathologies in a hospital in Corrientes Province, Argentina]. / Paracoccidioidomicosis asociada a otras patologías respiratorias en un hospital de Corrientes, Argentina.

For 2 years, a systematic research of paracoccidioidomycosis (PCM) had been conducted in a hospital in the city of Corrientes. The inclusion criterium used was: tuberculosis patients (TBC), presumptive or confirmed diagnosis of pulmonary cancer (CA), chronic obstructive pulmonary disease (COPD) and/or X-ray images compatible with pulmonary mycosis (XRC). Eighty four patients were studied: 57 (TBC), 1 (CA), 5 (COPD), 3 (TBC+CA), 4 (TBC+COPD), 4 (COPD+CA) and 10 (XRC). Serology tests by agar gel immunodiffusion (IDGA) were performed on all patients, whereas microbiological studies were performed on those cases in which clinical samples could be obtained. Ten PCM were diagnosed by IDGA; 4 associated to TBC, 1 to TBC+CA, 3 to COPD and only 2 to XRC. PCM was mycologically proven in 9 of these cases. Systematic research of PCM would lead to an early diagnosis and therefore, to better chances for a successful treatment.

Paracoccidioidomicosis asociada a otras patologías respiratorias en un hospital de Corrientes, Argentina / Association of paracoccidioidomycosis with different pulmonary pathologies in a hospital in Corrientes province, Argentina

Se realizó la búsqueda sistemática de paracoccidioidomicosis (PCM) en un conjunto de pacientes que fueron atendidos en un hospital de la ciudad de Corrientes dentro de un período de dos años. El criterio de inclusión fue: pacientes con tuberculosis (TBC), pacientes con diagnóstico presuntivo o confirmado de cáncer de pulmón (CA), pacientes con enfermedad pulmonar obstructiva crónica (EPOC) y pacientes con imagen radiológica compatible con micosis pulmonar (IRXC). Se estudiaron 84 pacientes: 57 con TBC, 1 con CA, 5 con EPOC, 3 con TBC+CA, 4 con TBC+EPOC, 4 con EPOC+CA y 10 con IRXC. A todos se les realizó serología por inmunodifusión en gel de agar (IDGA) y, en los casos en que se pudo obtener una muestra clínica, también se efectuaron estudios microbiológicos. Por IDGA se diagnosticaron 10 casos de PCM: 4 asociados a TBC, 1 a TBC+CA, 3 a EPOC y 2 a IRXC; 9 de ellos se corroboraron por el hallazgo del hongo. La búsqueda sistemática de PCM en habitantes del área endémica que presentan patología pulmonar favorecería el diagnóstico precoz y, por lo tanto, las posibilidades de un tratamiento eficaz.

For 2 years, a systematic research of paracoccidioidomycosis (PCM) had been conducted in a hospital in the city of Corrientes. The inclusion criterium used was: tuberculosis patients (TBC), presumptive or confirmed diagnosis of pulmonary cancer (CA), chronic obstructive pulmonary disease (COPD) and/or X-ray images compatible with pulmonary mycosis (XRC). Eighty four patients were studied: 57 (TBC), 1 (CA), 5 (COPD), 3 (TBC+CA), 4 (TBC+COPD), 4 (COPD+CA) and 10 (XRC). Serology tests by agar gel immunodiffusion (IDGA) were performed on all patients, whereas microbiological studies were performed on those cases in which clinical samples could be obtained. Ten PCM were diagnosed by IDGA; 4 associated to TBC, 1 to TBC+CA, 3 to COPD and only 2 to XRC. PCM was mycologically proven in 9 of these cases. Systematic research of PCM would lead to an early diagnosis and therefore, to better chances for a successful treatment.

In vitro activity of voriconazole against dermatophytes, Scopulariopsis brevicaulis and other opportunistic fungi as agents of onychomycosis.

Using a reference microdilution method, we studied the antifungal susceptibility to voriconazole and fluconazole of 304 clinical isolates from four species of onychomycosis-causing dermatophytes, 196 isolates of dermatophytes not related to nail infection as well as Scopulariopsis brevicaulis, Fusarium spp. and Scytalidium dimidiatum. Results showed a high antifungal activity of voriconazole against dermatophytes (geometric mean minimal inhibitory concentration (MIC)=1.14 microg/mL; MIC for 50% of the organisms (MIC(50))=0.062 miccrog/mL; MIC for 90% of the organisms (MIC(90))=0.25 microg/mL). For S. brevicaulis, the in vitro activity of voriconazole was considerably lower (geometric mean MIC=8.52 microg/mL; MIC(50) and MIC(90)=16 microg/mL). Although voriconazole is not among the drugs recommended for the management of onychomycosis, it can be a useful alternative for recalcitrant infections.

Antifungal agents: mode of action in yeast cells.

Different kinds of mycoses, especially invasive, have become an important public health problem as their incidence has increased dramatically in the last decades in relation to AIDS, hematological malignancies, transplant recipients and other immunosuppressed individuals. Management of fungal infections is markedly limited by problems of drug safety, resistance and effectiveness profile. Current therapy for invasive mycoses uses a relatively reduced number of antifungal drugs, such as amphotericin B, fluconazole and itraconazole. Other new antifungal agents from old and new chemical families, like voriconazole, posaconazole, ravuconazole, caspofungin and micafungin, have been introduced into the armamentarium for fungal infections management. This review is focused on the mode of action of those antifungal drugs used against pathogenic yeasts. The interaction of amphotericin B with ergosterol and other membrane sterols results in the production of aqueous pores of drug and the ergosterol biosynthetic pathway is the target of the allylamines, phenylmorpholines and azole antifungal agents. The main molecular target of azole antifungals is the cytochrome P-450 protein Erg11p/Cyp51p. Echinocandins, a new class of antifungal drugs, are fungal secondary metabolites that act against beta-1-3-D-glucan synthesis. The phenylmorpholines, of which amorolfine is the sole representative in human therapy, affect two targets in the ergosterol pathway: Erg24p (delta 14 reductase) and Erg2p (delta 8-delta 7 isomerase). The sordarins group are protein synthesis inhibitors that work by blocking the function of fungal translation elongation factor 2. Other protein inhibitors are zofimarin, BE31045, SCH57504, xylarin, hypoxysordarin and GR135402. In order to overcome the problems derived from the exploitation of azole drugs, macrolides and echinocandins, novel targets were explored. Proposed antifungal drugs have been developed against potential targets like the N-myristylation of fungal proteins, with inhibitors like myristate and histidine analogues or myristoylpeptide derivatives, aminobenzothiazoles, quinolines and benzofurans. Polymerization of cell wall carbohydrates from uridine di-phospho sugars is another potential target.

Antifungal agents: Mode of action in yeast cells

Different kinds of mycoses, especially invasive, have become an important public health problem as their incidence has increased dramaticallyin the last decades in relation to AIDS, hematological malignancies, transplant recipients and other immunosuppressed individuals.Management of fungal infections is markedly limited by problems of drug safety, resistance and effectiveness profile. Current therapy forinvasive mycoses uses a relatively reduced number of antifungal drugs, such as amphotericin B, fluconazole and itraconazole. Other newantifungal agents from old and new chemical families, like voriconazole, posaconazole, ravuconazole, caspofungin and micafungin, havebeen introduced into the armamentarium for fungal infections management. This review is focused on the mode of action of those antifungaldrugs used against pathogenic yeasts. The interaction of amphotericin B with ergosterol and other membrane sterols results in theproduction of aqueous pores of drug and the ergosterol biosynthetic pathway is the target of the allylamines, phenylmorpholines and azoleantifungal agents. The main molecular target of azole antifungals is the cytochrome P-450 protein Erg11p/Cyp51p. Echinocandins, a newclass of antifungal drugs, are fungal secondary metabolites that act against beta-1-3-D-glucan synthesis. The phenylmorpholines, of whichamorolfine is the sole representative in human therapy, affect two targets in the ergosterol pathway: Erg24p (delta 14 reductase) and Erg2p(delta 8–delta 7 isomerase). The sordarins group are protein synthesis inhibitors that work by blocking the function of fungal translationelongation factor 2. Other protein inhibitors are zofimarin, BE31045, SCH57504, xylarin, hypoxysordarin and GR135402. In order to overcomethe problems derived from the exploitation of azole drugs, macrolides and echinocandins, novel targets were explored. Proposed antifungaldrugs have been developed against potential targets like the N-myristylation of fungal proteins, with inhibitors like myristate and histidineanalogues or myristoylpeptide derivatives, aminobenzothiazoles, quinolines and benzofurans. Polymerization of cell wall carbohydratesfrom uridine di-phospho sugars is another potential target

Las micosis, especialmente las invasoras, se han convertido en un importante problema de salud al aumentar espectacularmente su incidenciadurante las últimas décadas en pacientes con sida, neoplasias hematológicas, trasplantes y otros tipos de inmunosupresión. Su tratamientoestá muy limitado por problemas de eficacia, resistencia y seguridad farmacológicas, y actualmente se utiliza un número relativamente reducidode antifúngicos, como amfotericina B, fluconazol e itraconazol. Otros nuevos antifúngicos, procedentes tanto de recientes familias químicascomo de las clásicas, se han introducido en los protocolos de las infecciones fúngicas. Esta revisión se centra en el mecanismo de acciónde los antifúngicos utilizados frente a levaduras patógenas. La interacción de amfotericina B con ergosterol y otros esteroles de membrana dacomo resultado la producción de poros acuosos y la vía biosintética del ergosterol es la diana sobre la que actúan las alilaminas, las fenilmorfolinasy los azoles. La principal diana molecular de los azoles es la proteína Erg11p/Cyp51p del citocromo P-450. Las equinocandinas son metabolitossecundarios fúngicos que inhiben la síntesis de beta-1-3-D-glucano. Las fenilmorfolinas, de las que amorolfina es la única utilizadaen humanos, afecta a dos dianas en la vía del ergosterol: Erg24p (delta 14 reductasa) y Erg2p (delta 8-delta 7 isomerasa). Las sordarinas soninhibidores de la síntesis proteica que bloquean la función del factor de elongación 2. Otros inhibidores proteicos son zofimarina, BE31045,SCH57504, xilarina, hipoxisordarina y GR135402. Con objeto de superar los problemas derivados del abuso de azoles, macrólidos y equinocandinas,se han explorado nuevas dianas y posibles antifúngicos frente a ellas,como los inhibidores de la N-miristilación de las proteínas fúngicas,por ejemplo miristato y análogos de la histidina o derivados miristoil peptidicos, aminobenzotiazoles, quinolinas y benzofuranos. La polimerizaciónde los hidratos de carbono de la pared celular procedentes de azúcares uridina difosfato es otra posible diana

Azole resistance in neonatal intensive care units in Argentina.

The aim of this study was to determine the antifungal susceptibility profile and to detect resistant strains of yeast species isolated from neonates in Intensive Care Units. 92 strains isolated from 25 bloodstream cultures, 20 venous catheters, 23 suprapubic aspirations and 24 rectal swabs were studied. A Candida glabrata strain resistant to fluconazole was detected. Candida krusei appeared with its inherent resistance to fluconazole and showed cross-resistance to itraconazole. Two Candida albicans strains were resistant to azoles, one to itraconazole and the other to fluconazole with a high minimum inhibitory concentration (MIC) for itraconazole. All Candida tropicalis strains were susceptible to fluconazole but two of them showed resistance to itraconazole. The detection of resistant strains in neonates whom had not received previous antifungal therapy is noteworthy. The variations in the epidemiology of fungal infections observed and the antifungal resistance detected emphasize the importance of performing a regular surveillance to observe and to assess them.

Yeasts species distribution in Neonatal Intensive Care Units in northeast Argentina.

The aim of this study was to determine the distribution and antifungal susceptibility profile of yeast species isolated from neonates in Neonatal Intensive Care Units (NICU) in northeast of Argentina. With this purpose 92 strains isolated from 25 blood stream cultures, 20 venous catheters, 23 suprapubic aspirations and 24 rectal swabs were studied. Candida albicans and C. parapsilosis appeared with similar frequencies (36%) in blood stream isolates. Candida parapsilosis (50%) was the most frequent catheters colonizer and C. tropicalis (54.2%) was the most frequent yeast associated with gastrointestinal tract colonization. Candida krusei, C. glabrata and Trichosporon cutaneum appeared with a very low frequency. A high rate of susceptibility to amphotericin B, fluconazole, and itraconazole was observed.

Identificación de especies de Malassezia por PCR-REA / Malassezia species identification with PCR-REA

Las especies del género Malassezia han adquirido importancia por su asociación a diversos procesos patológicos. Desde 1996 fueron clasificadas en M. pachydermatis, M. furfur, M. sympodialis, M. slooffae, M. obtusa, M. globosa y restricta. El esquema de identificación basado en las características morfológicas, fisiológicas y bioquímicas no siempre permite distinguir entre algunas de ellas. El objetivo de este trabajo fue poner a punto una metodología rapida, específica y eficaz para la identificación de las especies de este género. Con este fin, basados en la técnica de PCR-REA de Guillot y col., se introdujeron modificaciones en la metodología de extracción y purificación del ADN y en la electroforesis. Las variaciones propuestas en este trabajo confieren mayor practicidad a la técnica y disminuyen los costos. La obtención de resultados definidos permitiría a través de investigaciones taxonómicas y epidemiológicas avanzar en el estudio de la ecología, definir el rol patogénico y aumentar la información epidemiológica del género Malassezia (AU)

Identificación de especies de Malassezia por PCR-REA / Malassezia species identification with PCR-REA

Las especies del género Malassezia han adquirido importancia por su asociación a diversos procesos patológicos. Desde 1996 fueron clasificadas en M. pachydermatis, M. furfur, M. sympodialis, M. slooffae, M. obtusa, M. globosa y restricta. El esquema de identificación basado en las características morfológicas, fisiológicas y bioquímicas no siempre permite distinguir entre algunas de ellas. El objetivo de este trabajo fue poner a punto una metodología rapida, específica y eficaz para la identificación de las especies de este género. Con este fin, basados en la técnica de PCR-REA de Guillot y col., se introdujeron modificaciones en la metodología de extracción y purificación del ADN y en la electroforesis. Las variaciones propuestas en este trabajo confieren mayor practicidad a la técnica y disminuyen los costos. La obtención de resultados definidos permitiría a través de investigaciones taxonómicas y epidemiológicas avanzar en el estudio de la ecología, definir el rol patogénico y aumentar la información epidemiológica del género Malassezia

[Identification of Malassezia species by PCR-REA]. / Identificación de especies de Malassezia por PCR-REA.

The genus Malassezia has acquired relevance in the last years for its pathological associations. Since 1996, the genus comprises M. pachydermatis, M. furfur, M. sympodialis, M. slooffiae, M. obtusa, M. globosa and M. restricta. The identification scheme based on morphological, physiological and biochemical characteristics does not resolve ambiguity between some species. The aim of this study was to find out a fast, specific and efficient methodology to distinguish between Malassezia species. Based on a previous technique for polymerase chain reaction-restriction enzyme analysis (PCR-REA), modifications were applied on DNA extraction and purification and the electrophoresis. These changes produced a cheaper, reliable and rapid method as identification procedure with easily defined results. The proposed modifications would allow a better knowledge on ecological and pathogenic roles of Malassezia, studies that have not yet been established.

Identificación de especies de Malassezia por PCR-REA. / [Identification of Malassezia species by PCR-REA]

The genus Malassezia has acquired relevance in the last years for its pathological associations. Since 1996, the genus comprises M. pachydermatis, M. furfur, M. sympodialis, M. slooffiae, M. obtusa, M. globosa and M. restricta. The identification scheme based on morphological, physiological and biochemical characteristics does not resolve ambiguity between some species. The aim of this study was to find out a fast, specific and efficient methodology to distinguish between Malassezia species. Based on a previous technique for polymerase chain reaction-restriction enzyme analysis (PCR-REA), modifications were applied on DNA extraction and purification and the electrophoresis. These changes produced a cheaper, reliable and rapid method as identification procedure with easily defined results. The proposed modifications would allow a better knowledge on ecological and pathogenic roles of Malassezia, studies that have not yet been established.