16 research outputs found
ICMSF Methods Studies. XV. Comparison of Four Media and Methods for Enumerating Staphylococcus aureus in Powdered Milk.
Four media were examined for their usefulness in enumerating Staphylococcus aureus inoculated (a) into milk that was then dried or (b) directly into dried milk powder. In all, seven strains of S. aureus were inoculated individually into each preparation and were enumerated after two periods of storage (18 to 19 d and 60 to 61 d). Fourteen laboratories from twelve countries participated in the comparison which found that direct plating on agar medium in 14-cm petri dishes may be as useful as enrichment followed by streaking. Plating on Baird-Parker medium or on Hauschild pork plasma fibrinogen medium and a MPN method using Giolitti and Cantoni's broth with Tween 80 were equally sensitive for enumerating S. aureus in dried milk powder. The use of Hauschild medium may eliminate the need for supplementary tests to confirm colonies as S. aureus , but in some cases was found to fail in some laboratories. Giolitti and Cantoni's broth without Tween 80 generally was less useful than the three other media for enumerating S. aureus . S. aureus inoculated into milk that was then dried survived longer than when inoculated into dried milk
Evaluaci贸n sensorial del topinambur (Helianthus tuberosus L.) como alimento
Entre el 16 y el 20% del peso fresco del tub茅rculo de topinambur es inulina. Esta act煤a como prebi贸tico, favoreciendo el desarrollo de bacterias ben茅ficas en el colon. La harina de topinambur no tiene gluten, lo que la hace apta para cel铆acos; y adem谩s, tiene valor energ茅tico reducido. Con el objetivo de valorar el potencial del topinambur como alimento, y debido a la tendencia mundial hacia el consumo de comidas r谩pidas, se elaboraron productos saludables con topinambur: snacks (saborizados con queso parmesano, estevia y testigo), panificados (galletas dulces y saladas y magdalenas tradicionales e integrales) y pur茅 deshidratado (con variedades de topinambur de epidermis roja y de epidermis blanca). Se determin贸 la valoraci贸n general de los productos. Se consult贸 sobre la intenci贸n de compra de estos y la voluntad de consumo del alimento ligada al g茅nero. La evaluaci贸n sensorial de los snacks no mostr贸 diferencias entre ellos. En el caso de los panificados, la valoraci贸n general present贸 diferencias; las galletas dulces fueron significativamente mejor evaluadas que los dos tipos de magdalenas, las que no se diferenciaron entre s铆, y por 煤ltimo las galletas saladas fueron las menos apreciadas por los evaluadores. Los pur茅s deshidratados no presentaron diferencias significativas entre s铆. En l铆neas generales, las mujeres son las que muestran mayor voluntad de consumo
Caracterizaci贸n fenot铆pica y genot铆pica de la resistencia enzim谩tica a las cefalosporinas de tercera generaci贸n en Enterobacter spp. Phenotypic and genotypic characterization of resistance to third-generation cephalosporins in Enterobacter spp.
Enterobacter spp. es un pat贸geno intrahospitalario que presenta m煤ltiples mecanismos de resistencia a los antibi贸ticos b-lact谩micos. Se caracterizaron fenot铆pica y genot铆picamente las diferentes b-lactamasas presentes en 27 aislamientos consecutivos e ininterrumpidos de Enterobacter spp. (25 Enterobacter cloacae y 2 Enterobacter aerogenes). Tambi茅n se evalu贸 la habilidad de diferentes m茅todos fenot铆picos para detectar b-lactamasas de espectro extendido (BLEE) en estos microorganismos. En 15/27 aislamientos (63%) se observ贸 resistencia a las cefalosporinas de tercera generaci贸n. En 12 de los aislamientos resistentes se detect贸 un alto nivel de producci贸n de cefalosporinasa cromos贸mica, siendo 6 de ellos tambi茅n productores de PER-2. Dicha resistencia en los 3 aislamientos restantes se debi贸 exclusivamente a la presencia de BLEE, PER-2 en 2 de ellos y CTX-M-2 en un caso. S贸lo CTX-M-2 se detect贸 con todas las cefalosporinas probadas en los ensayos de sinergia, utilizando el m茅todo de difusi贸n, mientras que cefepima mejor贸 la detecci贸n de PER-2 en 7/8 aislamientos productores de esta BLEE, 4/8 utilizando la prueba de doble disco y 7/8 comparando discos de cefepima con y sin el agregado de 谩cido clavul谩nico. El m茅todo de diluci贸n empleado solo detect贸 1/9 BLEE al comparar las cefalosporinas con y sin el agregado de inhibidor.<br>Enterobacter spp. are becoming increasingly frequent nosocomial pathogens with multiple resistance mechanism to b-lactam antibiotics. We carried out the phenotypic and genotypic characterization of beta-lactamases in 27 Enterobacter spp. (25 Enterobacter cloacae y 2 Enterobacter aerogenes), as well as the ability of different extended spectrum b-lactamase (ESBL) screening methods. Resistance to third generation cephalosporins was observed in 15/27 (63%) isolates. Twelve resistant isolates produced high level chromosomal encoded AmpC b-lactamase; 6 of them were also producers of PER-2. Resistance to third generation cephalosporins in the remaining 3 isolates was due to the presence of ESBLs, PER-2 in 2 cases, and CTX-M-2 in the other. Only CTX-M-2 production was detected with all tested cephalosporins using difusion synergy tests, while cefepime improved ESBLs detection in 7/8 PER-2 producers, 4/8 in the inhibitor aproximation test and 7/8 with double disk test using cefepime containing disk with and without clavulanic acid. Dilution method, including cephalosporins with and without the inhibitor detected 1/9 ESBLs producers
Circannual variation of ef\ufb01cacy outcomes in patients with newly diagnosedmetastatic colorectal cancer and treated with \ufb01rst-line chemotherapy
Seasonal variation of baseline diagnosis (or clinical suspect) of stage I-III colorectal cancer patients has been repeatedly reported as an independent variable influencing overall survival. However, data are conflicting and no information is available about such a rhythm in advanced stage patients. To test whether a circannual rhythm of efficacy outcomes can be detected in this setting, we collected data about response rate (RR), progression-free survival (PFS), and overall survival (OS) to first-line chemotherapy of 1610 newly diagnosed metastatic patients treated at four independent centers. Responses to first-line chemotherapy were available for 1495 patients. A strong circannual rhythm in RR was evident, with the higher proportion of responding patients in the subgroup diagnosed in January (acrophase). At the time of data cutoff, 1322 patients progressed and 986 died, with median PFS and OS of 11 and 25.6 months, respectively. A circannual rhythmicity of the proportion of patients progressing at 6 months and surviving at 1 year was demonstrated, with acrophases located both in winter (February and January, respectively), similar to what reported for RR. Several interpretations about the genesis of this cyclic variation could be claimed: the rhythm in sunlight exposure and, as a consequence, of vitamin D serum levels and folate degradation, the variability in toxic effect intensity of chemotherapy, and the rhythm in the biological behavior of tumor cells. This observation is worth of further investigation both in preclinical and in clinical settings in order to better elucidate the underlying mechanisms