Manuel Casal

Contribution to the study of the enzymatic profiles of yeast organisms with medical interest

The enzymatic profiles of several yeastlike organisms were studied using 19 substrates included in the API ZYM system. The isolates evaluated were: 186 Candida albicans, 19 C. stellatoidea, 4 C. tropicalis, 2 C. parapsilosis, 2 C. pseudotropicalis, 1 C. guilliermondii, 3 C. krusei, 11 Torulopsis (Candida) glabrata, 1 Cryptococcus neoformans, 2 Saccharomyces carlsbergensis, 1 Rhodotorula rubra, and 1 R. mucilaginosa.Esterase lipase (C8), leucine arylamidase, acid phosphatase, and phosphoamidase were detected in all of the isolates while trypsin and α-galactosidase were not found in any of the isolates using this system. The other enzymes were produced to a variable degree. The different enzymatic profiles might prove useful in the rapid differential diagnosis of genera and species of these yeastlike organisms. To this end, more extensive studies using more isolates of each species will be required, and enzymatic activity should be verified with other techniques and substrates.

The comparison of six media for chlamydospore production by Candida albicans

Six different cultural media (corn meal agar, rice extract agar, chlamydospore agar, PCB, Tween 80-oxgall-caffeic acid and diluted milk) were compared for chlamydospore production by 224 yeastlike fungi isolates. Candida albicans formed chlamydospores to a variable degree in all of the media, as did C. stellatoidea to a lesser extent. C. tropicalis, C. parasilopsis, C. guilliermondii and C. krusei did not produce chlamydospores in any of the media tested. Statistically, the most productive media were the milk and TOC media. Milk medium is particularly useful because of its simplicity and economy.

First human case of possible Protothecosis in Spain

Prototheca wickerhamii was isolated from the stool of a two month-old infant with diarrhea resistant to treatment. This is the first description from Spain of algae of the genus Prototheca isolated from human clinical specimens. The possible pathogenicity of the Prototheca in this case is discussed.

Culture-Independent Prediction of Isoniazid Resistance in Mycobacterium tuberculosis by katG.Gene Analysis Directly From Sputum Samples

BACKGROUND The molecular prediction of isoniazid (INH) resistance in Mycobacterium tuberculosis is hampered by the need for specialized equipment, expertise, high costs, a limited range of detectable mutations, or several of these factors. The rationale for the study was to find a practical alternative and to demonstrate generally valid problems. METHODS AND RESULTS DNA extracted from decontaminated sputum pellets was used to amplify a 0.26 kb target sequence within the katG gene. Mutations of codon 315, frequently found in isoniazid-resistant isolates, could be discriminated in a simple agarose minigel format following an AciI digest of the nested polymerase chain reaction (PCR) product. Within a panel of 22 sputum samples, INH resistance could be predicted in 5 of 10 samples containing isoniazid-resistant M. tuberculosis. The protocol is robust, requires little expertise and no specialized equipment, and provides the test results within 2 days. CONCLUSION The results show the feasibility to rapidly and easily detect mutations highly predictive of isoniazid resistance. Nevertheless, this, like any other molecular resistance prediction test, is affected by often neglected factors, including mutation prevalences, the phenomenon of heteroresistance, and a possible bias toward ones own method.

Appearance of colonies of Prototheca on CHROMagar Candida medium.

The microorganisms capable of producing opportunist infections include the yeast-like organisms of the genus Candida, and the unicellular algae of the genus Prototheca, which share common features and can, therefore, lead to confusion. Their colonies are almost identical and they grow in the same culture media used routinely in mycology.CHROMagar Candida is a new chromogenic differential isolation medium that facilitates the presumptive differentiation of some of the most clinically important yeast-like organisms. To our knowledge, the use of CHROMagar Candida with Prototheca spp. has not been reported in the literature.This report describes the growth of 151 strains of Prototheca on CHROMagar Candida compared to the growth of a total of 326 well-characterized yeast organisms of the genera Candida, Cryptococcus, Trichosporon, Geotrichum, and Saccharomyces.It is clinically relevant to note that algae of the genus Prototheca (P. wickerhamii, P. zopfii, and P. stagnora) and of the genus Candida parapsilosis produced similar cream-colored colonies on CHROMagar Candida medium.Based on their growth on CHROMagar, a new species of Candida is described, C. zeylanoides, which has blue-green colonies. The colonies of two species of Trichosporon are also differentiated: the blue-green colonies of T. beigelii and the pink colonies of T. capitatum.

Cómo denominar a las micobacterias diferentes a Mycobacterium tuberculosis y a M. leprae

A review of the terms used to name mycobacteria other than M. tuberculosis and M. leprae was performed. A system using binomial nomenclature is defended. The author comments on the various names applied to mycobacteria over the history of medicine, from 1899 to the present, and the reasons why terms such as environmental mycobacteria or nontuberculous mycobacteria are incorrect and should not be used. In the case that a general name must be chosen for these mycobacteria, the term atypical mycobacteria is advocated.

Simple new test for presumptive differentiation between genus Candida and genus Prototheca

A differential test was made between genus Candida and genus Prototheca using a new and very simple differential test.A total of 59 strains of Candida and 78 strains of Prototheca were used. The basis of the test was the differential use of a disc carrying 60 mcg of Rybostamicin to which all the Candida were resistant and the Prototheca inhibited.

Investigacion preliminar de la accion inhibitoria in vitro de los antibioticos frente a las algas del genero Prototheca

ResumenSe investigó la posible acción inhibitoria ‘in vitro’ de antibióticos en disco sobre algas microscópicas, potencialmente patógenas para el hombre, del Género Prototheca y la especie P. wickerhamii.Se utilizó el método de disco-placa en medio de Agar de Saboureaud.Resultaron como inhibidores ‘in vitro’: Amikacina, Colistina, Dibekacina, Framicetina, Gentamicina, Kanamicina, Lividomicina, Neomicina, Polimixina, Paromomicina, Ribostamicina, Sisomicina y Tobramicina.Se destaca el interés del estudio de sensibilidad a estas drogas ante un caso de Protothecosis humana.AbstractWe investigated the possible inhibitory action ‘in vitro’ by antibiotic containing discs against microscopic alga that are potential human pathogens of the genus Prototheca especially P. wickerhamii.The results indicated that inhibitors in vitro included amicacin, colistin, dibecacin, framicetin, gentamycin, kanamycin, lividomycin, neomycin, polymyxin, paromomycin, ribostamycin, sisomycin and tobramycin.We emphasize the interest in the effectiveness at these drugs in a case of human protothecosis.

In vitro acitivity of ribostamycin against Prototheca sp.

The in vitro activity of ribostamycin against algae of the genus Prototheca was evaluated by minimum inhibitory concentration (MIC) studies on solid media. Concentrations of 4 mcg/ml were required to inhibit 100% of the P. zopfii strains; 16 mcg/ml inhibited 100% of the P. stagnora strains and 95% of the P. wickerhamii strains. These values are inferior to plasma concentrations obtained after injection of ribostamycin. It is likely that this antibiotic could be effective in the treatment of protothecosis in man.

Ocho siglos de la muerte de un gran médico: "Maimónides El Español"

Se cumplen este ano ocho siglos de la muerte del ilustre medico judio espanol nacido en Cordoba. Maimonides fue filosofo, teologo, jurista y medico. Sin embargo, el aspecto medico quiza sea el menos conocido de todos. En este articulo se hace un recorrido por la vida de Maimonides desde su nacimiento en Espana hasta su muerte, desde el punto de vista de su actividad y obra como medico. De una manera especial se repasan las enfermedades infecciosas por el abordadas en sus numerosos libros medicos, destacando la descripcion de la neumonia o la hepatitis, entre otras. Su pensamiento medico es aun hoy, en muchos aspectos, una valida orientacion para las nuevas generaciones de medicos.