RESUMEN Objetivos: En el presente trabajo se comparó el uso de proteínas de clara de huevo en soporte de alginato y alginato de calcio para la formulación. Material y Métodos: Tras la encapsulación de microorganismos en proteínas de clara de huevo en alginato, se evaluaron ensayos de supervivencia y liberación en diferentes condiciones. Para el análisis se han utilizado la microscopio electrónico con escáner y la espectroscopia infrarroja de transformada de Fourier. Resultados: Los resultados muestran el alto potencial de este tipo de formulación en la protección de los probióticos frente a las condiciones ácidas del estómago, por el aumento significativo en la supervivencia de las bacterias. Nuestro estudio demostró que la viabilidad de L. casei y L. acidophilus era mucho menor, sin embargo, con la encapsulación de las bacterias con proteínas de clara de huevo en alginato aumentaron significativamente su supervivencia especialmente para L. casei. La hinchazón y el comportamiento de contracción de las proteínas de clara de huevo en cápsulas de alginato en diferentes pH mostraron que la hinchazón de la cápsula en el agua destilada en términos neutros tenía más capacidad de inflación que una posición similar en términos de acidez gástrica. Conclusion: El uso de proteínas de clara de huevo-alginato para la encapsulación de probióticos mejora la estabilidad de estos microorganismos en condiciones adversas simuladas del medio gástrico.

ABSTRACT Aims: In the present study, we evaluated the use of egg white proteins in alginate scaffolds and calcium alginate for the formulation of Lactobacillus casei and Lactobacillus acidophilus in the stomach acidic conditions. Material and Methods: After microorganism’s encapsulation in egg white proteins in alginate, survival assays and release in different conditions were evaluated. Scanning electron microscope and Fourier-transform infrared spectroscopy were used for analysis. Results: The results showed the high potential of this type of formulation in protecting the probiotics from stomach acidic conditions that is due to the significant increase in survival of the bacteria. Our study showed that the viability of the L. casei to free L. acidophilus had much less, however, with the encapsulation of the bacteria Egg white proteins in Alginate increased their survival significantly. Specially for the L. casei. Swelling and shrinkage behavior of egg white proteins in alginate capsules in different pH showed that the swelling of the capsule in the distilled water in the neutral terms had more inflation- capacity than similar position in terms of gastric acidity. Conclusions: The use of egg white proteins-Alginate for encapsulation of probiotics enhanced the stability of these microorganisms in simulated gastric environments adverse conditions.

Abstract This study was conducted in Iran in order to assess the distribution of CTX-M type ESBLs producing Enterobacteriaceae. From January 2012 to December 2013, totally 198 E. coli, 139 Klebsiella spp, 54 Salmonella spp and 52 Shigella spp from seven hospitals of six provinces in Iran were screened for resistance to extended-spectrum cephalosporins. After identification and susceptibility testing, isolates presenting multiple-drug resistance (MDR) were evaluated for ESBL production by the disk combination method and by Etest using (cefotaxime and cefotaxime plus clavulanic acid). All isolates were also screened for bla CTX-M using conventional PCR. A total of 42.92%, 33.81%, 14.81% and 7.69% of the E. coli, Klebsiella spp, Salmonella spp and Shigella spp isolates were MDR, respectively. The presence of CTX-M enzyme among ESBL-producing isolates was 85.18%, 77.7%, 50%, and 66.7%, in E. coli, Klebsiella spp, Salmonella spp and Shigella spp respectively. The overall presence of CTX-M genes in Enterobacteriaceae was 15.4% and among the resistant isolates was 47.6%. This study indicated that resistance to β-lactams mediated by CTX-M enzymes in Iran had similar pattern as in other parts of the world. In order to control the spread of resistance, comprehensive studies and programs are needed.