[Examination of the genetic variability among biofilm-forming Candida albicans clinical isolates]. / Estudio de la variabilidad genética entre aislamientos clínicos de Candida albicans formadores de biopelículas.

Biofilms are microbial communities encased in a self-produced polymeric matrix and represent a common mode of microbial growth. Candida albicans is able to colonize the surface of catheters, prostheses, and epithelia, forming biofilms that are highly resistant to antimicrobial drugs. The objective of this study was the genotypic characterization of biofilm-forming C. albicans clinical isolates using RAPD (Random Amplified Polymorphic DNA). We have studied 25 clinical isolates of C. albicans from oral cavities, blood, skin, nail, stool, oesophagus biopsy and vaginal fluids from patients suffering from candidiasis. For each strain biofilm formation was analysed by measuring the ability to adhere to and grow on polystyrene plastic surfaces using XTT [2,3-bis(2-methoxi-4nitro-5sulfophenil)-2H tetrazolium-5carboxanilide] reduction assay. The similarity coefficients generated by RAPD using four different primers varied from 49 to 91%, indicating a high degree of genetic variability between the clinical isolates. The dendrogram clustered the isolates in four related groups, all groups included strains with very different abilities to form biofilms. The isolates with similar genotypes often showed very different biofilm formation abilities. Strains were grouped into clusters independently of their clinical sources. Our results suggested that a direct correlation does not exist between the biofilm-forming ability of natural populations of C. albicans and the genotype as determined by RAPD.

[Outbreak of histoplasmosis in province of Neuquén, Patagonia Argentina]. / Brote de histoplasmosis en la provincia de Neuquén, Patagonia Argentina.

BACKGROUND: In Argentina, there are no reports of autochthonous cases of histoplasmosis in the southern regions of the country. AIM: To report a histoplasmosis outbreak in Zapala town, Province of Neuquén, Patagonia Argentina. METHODS: We evaluated the clinical and epidemiological characteristics of 5 patients involved in the outbreak. Environmental studies were conducted to determine the source of infection. The genetic profile of Histoplasma capsulatum strains isolated from the index case (IC) were compared with clinical isolates from Argentinean patients not related to the outbreak, using RAPD-PCR with primers 1281-1283. RESULTS: The patients were residents of Zapala, and had not visited other geographical areas before. All patients had an influenza-like syndrome, and X-ray revealed disseminated micronodular images throughout the lung parenchyma. The IC needed specific antifungal therapy; the remaining 4 patients had mild symptoms, and did not require therapy. All of them had a good clinical outcome. Strains of H. capsulatum isolated from blood culture and lung biopsy of the IC showed a genetic profile different from other strains analyzed. The presence of the fungus in the environment was demonstrated by the detection of anti-Histoplasma antibodies in BALB/c mice inoculated with soil obtained in a culvert where workers had dug up earth after a landslide. CONCLUSIONS: This outbreak suggests the histoplasmosis endemic area is under the 38° S parallel. Patients from Neuquén, Patagonia Argentina, with compatible symptoms of histoplasmosis should be tested, regardless of their travel or exposure history.

Determination of the therapeutic activity of caspofungin compared with the amphotericin B in an animal experimental model of histoplasmosis in hamster (Mesocrisetus auratus).

BACKGROUND: Treatment with amphotericin B is highly effective in histoplasmosis. Caspofungin has shown good activity against Candida and Aspergillus spp. In vitro studies have demonstrated that Histoplasma capsulatum is inhibited by caspofungin. OBJECTIVES: The purpose of this study was to evaluate the effectiveness of caspofungin in the treatment of histoplasmosis in an animal experimental model. METHODS: Three strains of Histoplasma capsulatum var. capsulatum were used. Treatment started one week post-inoculation and the animals were randomly assigned to six groups: amphotericin B 6mg/Kg/d, caspofungin 2mg/Kg/d, 4mg/Kg/d, 8mg/Kg/d and the other two groups received saline solution and dextrose solution. Blood samples for culture were obtained once a week, from day 7 to 35 post-inoculation. One week after the end of the treatment the animals were sacrificed and spleen cultures were performed. RESULTS: Blood cultures were negative in all the hamsters which received amphotericin B (100%, P<0.001); those treated with caspofungin and the control animals presented 30 and 32% of positive cultures respectively (P=0.59). Spleen cultures were negative in the animals treated with amphotericin B, while the percentage of positive spleen cultures in the caspofungin groups varied from 25 to 100%, and in the control groups from 35 to 94.8% (P=0.07). The statistical analysis of the undiluted cultures showed the use of amphotericin B as the only independent predictor of negative culture (P<0.001). CONCLUSIONS: The efficacy of amphotericin B is well known for the treatment of histoplasmosis, though we could not demonstrate that caspofungin is better than control.

Genetic relatedness of subgingival and buccal Candida dubliniensis isolates in immunocompetent subjects assessed by RAPD-PCR.

BACKGROUND: It is recognized that Candida dubliniensis commonly colonizes oral and subgingival sites in immunocompetent subjects with periodontal disease. OBJECTIVE: Since there are few data available on genetic characterization of C. dubliniensis in periodontal pockets and other oral sites, the aim of this study was to characterize subgingival and mucosal C. dubliniensis isolates recovered from immunocompetent subjects and to assay the genetic similarity of such isolates from both niches in the same patient by random amplified polymorphic DNA (RAPD). DESIGN: C. dubliniensis recovered from subgingival plaque and from buccal cavity samples were studied in 240 immunocompetent non-smoking individuals. Arbitrary amplification was carried out by RAPD-polymerase chain reaction (PCR). RESULTS: RAPD analysis showed identical genotypes of C. dubliniensis in different sampling sites (buccal cavity and subgingival areas) in eight of 10 patients except for those derived from two participants who presented presumably unrelated isolates. CONCLUSIONS: On the basis of the findings presented, the origin of the colonization of C. dubliniensis in subgingival biofilm seems to be the buccal cavity in a single patient. Consequently, it may be assumed that most of C. dubliniensis in these sites arise from the endogenous commensal strains.

Brote de histoplasmosis en la provincia de Neuquén, Patagonia Argentina / Outbreak of histoplasmosis in province of Neuquén, Patagonia Argentina

Antecedentes. La República Argentina no registra casos autóctonos de histoplasmosis en regiones australes del país. Objetivo. Informar de un brote de histoplasmosis ocurrido en Zapala, Provincia de Neuquén, Patagonia Argentina. Métodos. Se evaluó el cuadro clínico y las características epidemiológicas de 5 pacientes involucrados en el brote. Se realizaron estudios ambientales para conocer la fuente de infección. Se analizó el perfil genético generado por RAPD-PCR con los primers 1281-1283 de los aislamientos de Histoplasma capsulatum del caso índice ( CI ) y se comparó con cepas de origen clínico no relacionadas con el brote. Resultados. Los pacientes residían en Zapala y no habían visitado otras áreas geográficas. Todos presentaron un síndrome gripal con imágenes radiológicas micronodulillares diseminadas. El CI necesitó tratamiento específico por la gravedad de su cuadro clínico, y los 4 pacientes restantes presentaron una sintomatología leve y no fueron tratados. La evolución clínica de todos fue favorable. Las cepas de H. capsulatum aisladas de hemocultivo y biopsia pulmonar del CI presentaron un perfil genético diferente al resto de las cepas analizadas. La presencia del hongo en el ambiente pudo inferirse mediante la detección de anticuerpos anti-Histoplasma en suero de ratones BALB/c inoculados con tierra de una alcantarilla que los trabajadores removieron después de un aluvión. Conclusiones. Este brote extiende el área endémica de histoplasmosis por debajo del paralelo 38° de latitud sur. El diagnóstico de histoplasmosis debe considerarse en pacientes de Neuquén, con síntomas compatibles con esta micosis, aun sin existir antecedentes epidemiológicos de viajes a áreas endémicas (AU)

Background: In Argentina, there are no reports of autochthonous cases of histoplasmosis in the southern regions of the country. Aim: To report a histoplasmosis outbreak in Zapala town, Province of Neuquén, Patagonia Argentina. Methods: We evaluated the clinical and epidemiological characteristics of 5 patients involved in the outbreak. Environmental studies were conducted to determine the source of infection. The genetic profile of Histoplasma capsulatum strains isolated from the index case (IC) were compared with clinical isolates from Argentinean patients not related to the outbreak, using RAPD-PCR with primers 1281-1283. Results: The patients were residents of Zapala, and had not visited other geographical areas before. All patients had an influenza-like syndrome, and X-ray revealed disseminated micronodular images throughout the lung parenchyma. The IC needed specific antifungal therapy; the remaining 4 patients had mild symptoms, and did not require therapy. All of them had a good clinical outcome. Strains of H. capsulatum isolated from blood culture and lung biopsy of the IC showed a genetic profile different from other strains analyzed. The presence of the fungus in the environment was demonstrated by the detection of anti- Histoplasma antibodies in BALB/c mice inoculated with soil obtained in a culvert where workers had dug up earth after a landslide. Conclusions: This outbreak suggests the histoplasmosis endemic area is under the 38◦ S parallel. Patients from Neuquén, Patagonia Argentina, with compatible symptoms of histoplasmosis should be tested, regardless of their travel or exposure history (AU)

Evaluación de la actividad de caspofungina comparada con anfotericina B en un modelo experimental de histoplasmosis en hámsters (Mesocrisetus auratus) / Determination of the therapeutic activity of caspofungin compared with the amphotericin B in an animal experimental model of histoplasmosis in hamster (Mesocrisetus auratus)

Antecedentes. La anfotericina B es un fármaco efectivo para el tratamiento de la histoplasmosis. La caspofungina es activa contra especies de Candida y Aspergillus. Estudios in vitro han demostrado el efecto inhibitorio de este fármaco en Histoplasma capsulatum. Objetivo. Evaluar la eficacia de la caspofungina comparada con la anfotericina B para el tratamiento de histoplasmosis en un modelo experimental en hámster. Métodos. Se utilizaron tres cepas de Histoplasma capsulatum var. capsulatum. El tratamiento comenzó una semana tras la inoculación y los animales fueron distribuidos aleatoriamente en 6 grupos, según los fármacos utilizados: anfotericina B 6mg/kg/día, caspofungina en dosis de 2, 4 y 8mg/kg/día, solución fisiológica y dextrosa al 5%. Se tomaron muestras semanales para hemocultivos a partir del séptimo día postinfección y a los 7 días de finalizado el tratamiento los animales fueron sacrificados, realizándose cultivos del bazo. Resultados. Los resultados obtenidos de los hemocultivos realizados al finalizar el tratamiento fueron negativos en un 100% en el grupo tratado con anfotericina B, frente al 30% en el grupo tratado con caspofungina y el 32% en el grupo control (p=0,59). Los cultivos de bazo fueron negativos en el grupo de anfotericina B, mientras que en el grupo de caspofungina los valores fluctuaron entre el 25 y el 100%, y en el grupo control entre el 35 y el 94,8% (p=0,07). En el análisis estadístico del cultivo de la suspensión de bazo sin diluir el uso de anfotericina B fue el único predictor independiente de cultivos negativos (p=0,001). Conclusiones. La anfotericina B es un fármaco efectivo para el tratamiento de la histoplasmosis. La administración de caspofungina no demostró mayor eficacia en comparación con el grupo control(AU)

Background. Treatment with amphotericin B is highly effective in histoplasmosis. Caspofungin has shown good activity against Candida and Aspergillus spp. In vitro studies have demonstrated that Histoplasma capsulatum is inhibited by caspofungin. Objectives. The purpose of this study was to evaluate the effectiveness of caspofungin in the treatment of histoplasmosis in an animal experimental model. Methods. Three strains of Histoplasma capsulatum var. capsulatum were used. Treatment started one week post-inoculation and the animals were randomly assigned to six groups: amphotericin B 6mg/Kg/d, caspofungin 2mg/Kg/d, 4mg/Kg/d, 8mg/Kg/d and the other two groups received saline solution and dextrose solution. Blood samples for culture were obtained once a week, from day 7 to 35 post-inoculation. One week after the end of the treatment the animals were sacrificed and spleen cultures were performed. Results. Blood cultures were negative in all the hamsters which received amphotericin B (100%, P<0.001); those treated with caspofungin and the control animals presented 30 and 32% of positive cultures respectively (P=0.59). Spleen cultures were negative in the animals treated with amphotericin B, while the percentage of positive spleen cultures in the caspofungin groups varied from 25 to 100%, and in the control groups from 35 to 94.8% (P=0.07). The statistical analysis of the undiluted cultures showed the use of amphotericin B as the only independent predictor of negative culture (P<0.001). Conclusions. The efficacy of amphotericin B is well known for the treatment of histoplasmosis, though we could not demonstrate that caspofungin is better than control(AU)

Estudio de la variabilidad genética entre aislamientos clínicos de Candida albicans formadores de biopelículas / Examination of the genetic variability among biofilm-forming Candida albicans clinical isolates

Las biopelículas están constituidas por microcolonias incluidas dentro de unamatriz polimérica y representan una forma de crecimiento microbiano.Candida albicans puede colonizar las superficies de catéteres, prótesis yepitelios formando biopelículas que son resistentes a las drogas antifúngicas.El objetivo de este trabajo fue la caracterización genotípica de aislamientosclínicos de C. albicans formadores de biopelículas usando la técnica RAPD(Random Amplified Polymorphic DNA).Fueron estudiados 25 aislamientos clínicos de C. albicans de fauces, sangre,piel, uñas, materia fecal, biopsia de esófago, y flujo vaginal de pacientescon candidiasis. Cada cepa fue previamente analizada en su capacidad decrecer y adherirse a la superficie de poliestireno, y la cuantificación de labiopelícula formada fue realizada mediante el ensayo de reducción de XTT[2,3-bis (2-metoxi-4 nitro-5 sulfofenil) -2 H tetrazolio-5 carboxanilida].Los coeficientes de similitud generados por RAPD variaron entre el 49 y el 91%con los cuatro iniciadores usados, revelando un alto nivel de variabilidadgenética. El dendrograma agrupó los aislamientos en cuatro grupos, incluyendotodos ellos cepas con muy diferente capacidad para formar biopelículas.Aislamientos con genotipos similares mostraron diferente capacidad deformación de biopelículas. Las cepas fueron agrupadas independientemente delorigen de la muestra. Nuestros resultados sugieren que en poblacionesnaturales de C. albicans no existe correlación entre la capacidad de formarbiopelículas y el genotipo determinado por PCR-RAPD(AU)

Biofilms are microbial communities encased in a self-produced polymeric matrixand represent a common mode of microbial growth. Candida albicans is able tocolonize the surface of catheters, prostheses, and epithelia, forming biofilms thatare highly resistant to antimicrobial drugs. The objective of this study was thegenotypic characterization of biofilm-forming C. albicans clinical isolates usingRAPD (Random Amplified Polymorphic DNA).We have studied 25 clinical isolates of C. albicans from oral cavities, blood, skin,nail, stool, oesophagus biopsy and vaginal fluids from patients suffering fromcandidiasis. For each strain biofilm formation was analysed by measuring theability to adhere to and grow on polystyrene plastic surfaces using XTT [2,3-bis(2-methoxi-4nitro-5sulfophenil) -2H tetrazolium-5carboxanilide] reduction assay.The similarity coefficients generated by RAPD using four different primers variedfrom 49 to 91%, indicating a high degree of genetic variability between theclinical isolates. The dendrogram clustered the isolates in four related groups, allgroups included strains with very different abilities to form biofilms. The isolateswith similar genotypes often showed very different biofilm formation abilities.Strains were grouped into clusters independently of their clinical sources.Our results suggested that a direct correlation does not exist between thebiofilm-forming ability of natural populations of C. albicans and the genotype asdetermined by RAPD(AU)