Gluconacetobacter medellinensis sp. nov., cellulose- and non-cellulose-producing acetic acid bacteria isolated from vinegar.

The phylogenetic position of a cellulose-producing acetic acid bacterium, strain ID13488, isolated from commercially available Colombian homemade fruit vinegar, was investigated. Analyses using nearly complete 16S rRNA gene sequences, nearly complete 16S-23S rRNA gene internal transcribed spacer (ITS) sequences, as well as concatenated partial sequences of the housekeeping genes dnaK, groEL and rpoB, allocated the micro-organism to the genus Gluconacetobacter, and more precisely to the Gluconacetobacter xylinus group. Moreover, the data suggested that the micro-organism belongs to a novel species in this genus, together with LMG 1693(T), a non-cellulose-producing strain isolated from vinegar by Kondo and previously classified as a strain of Gluconacetobacter xylinus. DNA-DNA hybridizations confirmed this finding, revealing a DNA-DNA relatedness value of 81 % between strains ID13488 and LMG 1693(T), and values <70 % between strain LMG 1693(T) and the type strains of the closest phylogenetic neighbours. Additionally, the classification of strains ID13488 and LMG 1693(T) into a single novel species was supported by amplified fragment length polymorphism (AFLP) and (GTG)5-PCR DNA fingerprinting data, as well as by phenotypic data. Strains ID13488 and LMG 1693(T) could be differentiated from closely related species of the genus Gluconacetobacter by their ability to produce 2- and 5-keto-d-gluconic acid from d-glucose, their ability to produce acid from sucrose, but not from 1-propanol, and their ability to grow on 3 % ethanol in the absence of acetic acid and on ethanol, d-ribose, d-xylose, sucrose, sorbitol, d-mannitol and d-gluconate as carbon sources. The DNA G+C content of strains ID13488 and LMG 1693(T) was 58.0 and 60.7 mol%, respectively. The major ubiquinone of LMG 1693(T) was Q-10. Taken together these data indicate that strains ID13488 and LMG 1693(T) represent a novel species of the genus Gluconacetobacter for which the name Gluconacetobacter medellinensis sp. nov. is proposed. The type strain is LMG 1693(T) ( = NBRC 3288(T) = Kondo 51(T)).

Bacterial cellulose produced by a new acid-resistant strain of Gluconacetobacter genus.

A bacterial strain isolated from the fermentation of Colombian homemade vinegar, Gluconacetobacter medellensis, was investigated as a new source of bacterial cellulose (BC). The BC produced from substrate media consisting of various carbon sources at different pH and incubation times was quantified. Hestrin-Schramm (HS) medium modified with glucose led to the highest BC yields followed by sucrose and fructose. Interestingly, the microorganisms are highly tolerant to low pH: an optimum yield of 4.5 g/L was achieved at pH 3.5, which is generally too low for other bacterial species to function. The cellulose microfibrils produced by the new strain were characterized by scanning and transmission electron microscopy, infrared spectroscopy X-ray diffraction and elemental analysis. The morphological, structural and chemical characteristics of the cellulose produced are similar to those expected for BC.

Estudio comparativo de los métodos de Kato Katz y de Beaver modificado para el recuento de huevos de helmintos / Comparative study of the Kato Katz method and the modified Beaver technic for parasite egg count

Después de revisar varios trabajos sobre métodos de recuento de huevos de helmintos, analizamos el de Kato Katz y lo comparamos son el método de Beaver modificado. Para este estudio escogimos una comunidad para recuperación de gamines, con una población de 250 estudiantes y 13 profesores, a todos los cuales se les hizo estudio de materia fecal por los dos métodos. El método de Kato Katz detectó más infecciones por Trichuris trichiura, uncinarias y Ascaris Iumbricoides, con diferencia estadíticamente significativa para los dos primeros

Tratamiento de amebiasis intestinal con Secnidazol. II. Estudio doble ciego en portadores asintomáticos

Se estudiaron 100 portadores asintomáticos de Entoameba histolytica o de Entameba hartmanni, ameba no patógena que frecuentemente se confunde con la primera. Se dividieron al azar en dos grupos que recibieron secnidazol o placebo en dosis única. El secnidazol se administró, de acuerdo con la edad, a una dosis promedio de 30 mg/kg. Se hicieron controles parasitológicos post-tratamiento a la una y dos semanas y se encontró que hubo negativización en 56 por ciento de los que recibieron antiamibiano y solo en 24 por ciento de los que recibieron placebo. La tolerancia fue buena, no hubo reacciones tóxicas.