Molecular epidemiology of Aspergillus species and other moulds in respiratory samples from Argentinean patients with cystic fibrosis.

In cystic fibrosis (CF) patients, fungal colonization of the respiratory tract is frequently found. Aspergillus fumigatus is the most frequently recorded and is associated with loss of pulmonary function and allergic disease (ABPA). The knowledge on prevalence rates of filamentous fungi in CF patients in Latin America is scarce. One hundred and seventy-six fungal isolates recovered from the upper respiratory tract of CF patients from Argentina were identified to species by morphology and DNA sequencing. In total, 90% of CF patients were colonized by Aspergillus sp., followed by Exophiala sp. (14%) and Scedosporium sp. (10%). Among Aspergillus, six species complexes (Fumigati, Flavi, Terrei, Nigri, Usti, and Nidulante) and different cryptospecies were found. Among Scedosporium, three species were observed (Scedosporium apiospermum, Scedosporium aurantiacum and Scedosporium boydii). All Exophiala isolates were identified as Exophiala dermatitidis. Rare filamentous fungi were also found. All cases of ABPA were associated to the presence of A. fumigatus. Mixed colonization with other mould or rare fungi was observed in half of them. To our knowledge, this is the first prospective study of mould species in CF using molecular methods in Latin America. This study shows that Aspergillus sp., E. dermatitidis and Scedosporium sp. have a high frequency in CF patients from Argentina, and by far, A. fumigatus was the most commonly cultured species. Continuous clinical surveillance is required to detect the emergence of new fungal pathogens and to detect resistant or difficult-to-treat species capable of chronic colonizing the airways and of hematogenous dissemination in case of lung transplantation.

Value of Etest penicillin V and penicillin G strips for penicillin susceptibility testing of Neisseria meningitidis.

The NCCLS agar dilution method and Etest are currently accepted methods for susceptibility testing of Neisseria meningitidis to penicillin. We determined the MIC of penicillin V and penicillin G by both the agar dilution method and Etest using 43 strains of N. meningitidis. Although results for reference strains were within the accepted quality control range of penicillin MICs for both drugs, differences of two to three dilutions were seen between the two antibiotics with both methods. Penicillin V results cannot correctly predict the susceptibility to penicillin G for N. meningitidis if penicillin G breakpoints are used for penicillin V. However, adjusting the penicillin V breakpoints two dilutions higher (i.e., S < or = 0.25 and R > or = 8 microg/ml), concordance could be achieved for susceptibility categorization by the two compounds. An agreement of 98% +/- 1 dilution was obtained between Etest and the reference method when using penicillin G strips. We conclude that Etest with penicillin G strips is a convenient and reliable alternative method for determining the MICs of penicillin for N. meningitidis.

[Epidemiology of fungaemia in a paediatric hospital of high complexity]. / Epidemiología de las fungemias en un hospital pediátrico de alta complejidad.

BACKGROUND: A retrospective study on the epidemiology of fungaemia due to yeasts of medical importance at the Hospital Nacional de Pediatría Prof. Dr. J. Garrahan, Buenos Aires was conducted between September 2001 and September 2003. OBJECTIVES: To learn the distribution of yeast species and to evaluate their in vitro antifungal susceptibility profile. METHODS: The minimum inhibitory concentration (MIC) was determined according to the CLSI M27-A2 procedure, and time kill curves against amphotericin B were also performed. RESULTS-CONCLUSIONS: The species isolated were Candida parapsilosis (32.6% of isolates); Candida albicans (26.5%), Candida tropicalis (24.5%), and other yeasts (16.4%). Candida isolates were susceptible to the antifungals evaluated, but amphotericin B-tolerant isolates were detected using time kill curves.

Epidemiología de las fungemias en un hospital pediátrico de alta complejidad / Epidemiology of fungaemia in a paediatric hospital of high complexity

Antecedentes. Se realizó un estudio retrospectivo desde septiembre de 2001 a septiembre de 2003 de las fungemias por levaduras en el Hospital Nacional de Pediatría Prof. Dr. J. Garrahan, de Buenos Aires. Objetivos. Conocer la distribución de las especies de levaduras de interés médico y evaluar el perfil de sensibilidad in vitro a los antifúngicos. Métodos. Se determinó la concentración mínima inhibitoria (CMI) según el documento M27-A2 del CLSI, y además, las curvas de letalidad frente a la anfotericina B. Resultados-Conclusiones. Se aislaron Candida parapsilosis (32,6% de los aislamientos), Candida albicans (26,5%), Candida tropicalis (24,5%), y otras especies de levaduras (16,4%). Los aislamientos de Candida fueron sensibles a los antifúngicos evaluados pero se detectaron, mediante el uso de curvas de letalidad, cepas tolerantes a la anfotericina B(AU)

Background. A retrospective study on the epidemiology of fungaemia due to yeasts of medical importance at the Hospital Nacional de Pediatría Prof. Dr. J. Garrahan, Buenos Aires was conducted between September 2001 and September 2003. Objectives. To learn the distribution of yeast species and to evaluate their in vitro antifungal susceptibility profile. Methods. The minimum inhibitory concentration (MIC) was determined according to the CLSI M27-A2 procedure, and time kill curves against amphotericin B were also performed. Results-Conclusions. The species isolated were Candida parapsilosis (32.6% of isolates); Candida albicans (26.5%), Candida tropicalis (24.5%), and other yeasts (16.4%). Candida isolates were susceptible to the antifungals evaluated, but amphotericin B-tolerant isolates were detected using time kill curves(AU)

Funguemia en pacientes pediátricos: aspectos taxonómicos y clínicos [poster] / Fungemia pediatrics patient: taxonomy and clinical feature [poster]

Se analizaron 80 pacientes con 82 episodios de fungemia, en un período de 3 años (enero 1989-enero 1992). Metodología: detección, aislamiento e identificación de las distintas especies. Se enuncian factores predisponentes, clínica, tratamiento y evolución de los pacientes

Estudio comparativo de Etest y dilución en medio líquido para determinar la sensibilidad a penicilina y ceftriaxona en Streptococcus pneumoniae / Comparative study between etest and broth dilution methods for penicillin and cerftriaxone susceptibility testing of streptococcus pneumoniae

La complejidad de los métodos de dilución y la falta de precisión del método de difusión en la clasificación entre cepas resistentes e intermedias de Streptococcus pneumoniae determinaron que algunos autores adoptaran exitosamente el método de Etest. El objetivo de este trabajo fue comparar en forma prospectiva y a doble ciego la sensibilidad a penicilina (PEN) y a ceftriaxona (CRO) obtenida por E-test y macrodilución en medio líquido para S. pneumoniae. Se emplearon 169 aislamientos de S. pneumoniae obtenidos entre 1997 y 2001. Por Etest se logró determinar correctamente la CIM de PEN y CRO en un 79,4 por ciento y un 81,2 por ciento de los aislamientos dentro de un rango de ±1 dilución. Con CRO se observó un 5 por ciento de errores very major y un 18,7 por ciento de errores minor. Con PEN se registró un 20 por ciento de errores minor pero no se detectaron errores major ni very major. Para PEN la mitad de las discrepancias fueron intrascendentes pues se registraron dentro de la categoría de sensibilidad. Por otra parte, los errores observados con CRO podrían disminuir sensiblemente si se adoptara el cambio de ¾ 0,5 µg/ml a ¾ 0,25 µg/ml como punto de corte para establecer sensibilidad por Etest

Método rápido de aglutinación del látex por hisopado faringeo para el diagnóstico de faringitis por estreptococo beta-hemolítico grupo A / Rapid method of latex agglutination by throat swals for the diagnosis of pharyngitis due to beta hemolytic Streptococcus group A

Entre mayo y agosto de 1985 se realizó un estudio con el fin de evaluar la precisión de una prueba diagnóstica rápida, basada en la aglutinación de partículas de látex sensibilizadas con anticuerpos específicos, para la identificación directa del estreptococo ß-hemolítico grupo A, comparándola con el método convencional de cultivo de fauces. Se obtuvieron simultáneamente 2 muestras de 836 niños con faringitis, atendidos por Consultorios Externos en el Hospital de Niños "R. Gutiérrez". El procedimiento de cultivo convencional consistió en incubación de las muestras durante 48 horas a 35-C. Las colonias que exhibieron ß-hemólisis fueron confirmadas como pertenecientes al grupo A mediante la prueba de coaglutinación. La sensibilidad y la especificidad del procedimiento evaluado fueron 91,0% y 97,1% respectivamente. El test resultó simple, de fácil realización y más exacto que la prueba de sensibilidad a la bacitracina