Susceptibilidad antimicrobiana de aislamientos de Salmonella enterica provenientes de pisos, equipos, utensilios y producto terminado en el beneficio porcino en Colombia

<p>La diseminación de aislamientos de Salmonella spp resistentes a antimicrobianos, a través de las cadenas productivas de alimentos de origen animal, es una preocupación de salud pública de carácter mundial. Éste estudio describe los patrones de resistencia antimicrobiana de 283 aislamientos de Salmonella enterica procedentes de plantas de beneficio porcino en Colombia. Se evaluó la susceptibilidad antimicrobiana frente a diez antimicrobianos: amoxacilina-ácido clavulánico (30 ug),  ampicilina(10 ug), ceftiofur (30 ug), ciprofloxacina (5 ug), cloranfenicol (30 ug), florfenicol (30 ug),  gentamicina (10 ug), sulfadiazina/trimetroprim (25 ug), tetraciclina (30 ug) y tilmicosina (15 ug) mediante el método de difusión en disco (Bauer &amp; Kirby, 1966). Los resultados evidenciaron la presencia de 279 aislamientos multiresistentes de Salmonella enterica de origen porcino provenientes del ambiente y producto terminado de las plantas de beneficio evaluadas (46.64% n: 132).  Se detectaron 52 patrones de multiresistencia, el más común fue ceftiofur-tetraciclina-tilmicosina en el 9,89% (n: 28) de los aislamientos. Con referencia a éstos antimicrobianos el 96,82% (n: 274) de los aislamientos fueron resistentes a tetraciclina, 73,14% (n: 207) a tilmicosina y 28,27% (n: 80)  a ceftiofur. De especial interés fue la alta proporción de aislamientos resistentes a éste último, debido a una posible resistencia cruzada con ceftriaxona. Los resultados obtenidos demuestran la necesidad de promover y fortalecer un Programa oficial de  Vigilancia de la Resistencia Antimicrobiana y  sistemas de monitoreo voluntario en cada eslabón de las cadenas productivas, para contribuir a la prevención y control de la transmisión de microorganismos  resistentes de origen alimentario en el marco del sistema de gestión de inocuidad alimentaria en Colombia.</p>

Naturally occurring heavy radioactive elements in the geothermal microcosm of the Los Azufres (Mexico) volcanic complex

The Los Azufres geothermal complex of central Mexico is characterized by fumaroles and boiling hot-springs. The fumaroles form habitats for extremophilic mosses and ferns. Physico-chemical measurements of two relatively pristine fumarolic microcosms point to their resemblance with the paleo-environment of earth during the Ordovician and Devonian periods. These geothermal habitats were analysed for the distribution of elemental mass fractions in the rhizospheric soil (RS), the native volcanic substrate (VS) and the sediments (S), using the new high-sensitivity technique of polarized x-ray energy dispersive fluorescence spectrometry (PEDXRF) as well as instrumental neutron activation analysis (INAA) for selected elements. This work presents the results for the naturally occurring heavy radioactive elements (NOHRE) Bi, Th and U but principally the latter two. For the RS, the density was found to be the least and the total organic matter content the most. Bi was found to be negligibly present in all substrate types. The average Th and U mass fractions in the RS were higher than in the VS and about equal to their average mass fractions in the S. The VS mass fraction of Th was higher, and of U lower, than the mass fractions in the earth's crust. In fact for the fumaroles of one site, the average RS mass fractions of these elements were higher than the averaged values for S (without considering the statistical dispersion). The immobilization of the NOHRE in the RS is brought about by the bio-geochemical processes specific to these extremophiles. Its effectiveness is such that despite the small masses of these plants, it compares with, or may sometimes exceed, the immobilization of the NOHRE in the S by the abiotic and aggressive chemical action of the hot-springs. These results indicate that the fumarolic plants are able to transform the volcanic substrate to soil and to affect the NOHRE mass fractions even though these elements are not plant nutrients. Mirrored back to the paleo times when such plant types were ubiquitous, it would mean that the first plants contributed significantly to pedogenesis and the biogeochemical recycling of even the heaviest and radioactive elements. Such plants may potentially be useful for the phytostabilisation of soil moderately contaminated by the NOHRE. Furthermore where applicable, geochronology may require taking into account the influence of the early plants on the NOHRE distributions.

Standards for mesiodistal and buccolingual crown size and height of primary molars in a sample of Spanish children

AIM

The aim of this study was to obtain mesiodistal, buccolingual and height sizes of dental crowns of first and second primary molars in a sample of Spanish children given, not only their anthropological and forensic significance, but also their clinical interest for the future analysis of restorative and orthodontic treatments.

MATERIALS AND METHODS

Measurements of mesiodistal, buccolingual size and height of the crowns of primary molars were studied. A transversally descriptive design was carried out and the interrelationship between these three dimensions was established. A sample of 703 first and second primary molars was selected from healthy Spanish boys and girls from 4 to 9 years old. Molars presenting anomalies of the crowns, caries or restorations were excluded. Measurements were made on dental plaster models, using a vernier caliper. Descriptive statistics and Pearson correlation coefficient was obtained and Wilcoxon's non- parametric test was applied for comparison of the mean, analysis of sexual dimorphism and comparison of antimeric teeth.

RESULTS

Average sizes of each group of molars were obtained. Sexual dimorphism was studied utilizing the Wilcoxon test. A variability of relationship between the measurements was found in each molar studied. Primary second molars had less variability than first molars in the three measurements obtained. The measurement with the least variability was height, followed by mesiodistal size.

CONCLUSIONS

Measurements of primary molars showed that average sizes of boys' molars were significantly larger than those of girls. Relationship between the three measurements studied was variable but second molars showed less variability than first molars. The relationship between height and width was found significant in most of the molars. i.

Developing expressed sequence tags (ESTs) from polymorphic transcript-derived fragments (TDFs) in cassava (Manihot esculenta Crantz)

We applied the cDNA-AFLP (amplified fragment length polymorphism) technique to mRNA from the parents of a cassava (Manihot esculenta) genetic mapping population, and obtained more than 500 transcript-derived fragments (TDFs) that were unique in either parent. A subset of 50 TDFs were cloned and sequenced. Sequence alignment of the expressed sequence tags (ESTs) revealed mostly genes of unknown function. Six of the TDFs were mapped on to the cassava genetic map. We also demonstrated by genetic mapping of the TDFs, as RFLP (restriction fragment length polymorphism) markers, that TDFs are more polymorphic than random cDNAs. Generation of ESTs as differentially expressed sequences, in time or between different varieties, is proposed as a way of developing ESTs around specific traits for the candidate locus approach to mapping complex traits.

Preliminary pharmacobiological study of new steroidal sapogenins

The chemotherapeutic study of a limited series of steroidal sapogenins from several endemic species of the flora of the Canary Islands is presented here. On the whole, they possess a very weak antibacterial activity, a slight antifungal effect and one of them, vespertilin, displays interesting cytostatic activity (ID50 = 5 micrograms/ml). A pharmacodynamic screening carried out on this product mainly revealed very slight toxicity, antihistaminic activity and a light tranquilizing effect. The data obtained justify further research.