Changing Epidemiology of Extended-Spectrum β-Lactamases in Argentina: Emergence of CTX-M-15

A multicenter survey, carried out in 2010 in Argentina, showed an increased prevalence of extended-spectrum p-lactamase (ESBL)-producing enterobacteria, with some changes in the molecular epidemiology of circulating ESBLs. While enzymes of the CTX-M-2 group remain endemic, the emergence of CTX-M-15 and of enzymes of the CTX-M-8 and CTX-M-9 groups was observed. The CTX-M-15-positive isolates represented 40% of CTX-M producers and included representatives of Escherichia coli ST131 and Klebsiella pneumoniae ST11.Fil: Sennati, S.. Università degli Studi di Siena; ItaliaFil: Santella, G.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Microbiología; ArgentinaFil: Di Conza, José Alejandro. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Pallecchi, L.. Università degli Studi di Siena; ItaliaFil: Pino, Marylú. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Ghiglione, Barbara. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Rossolini, G.M.. Università degli Studi di Siena; ItaliaFil: Radice, Marcela Alejandra. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; ArgentinaFil: Gutkind, Gabriel Osvaldo. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Microbiología, Inmunología y Biotecnología. Cátedra de Microbiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay; Argentin

De novo assembly of a transcriptome from the eggs and early embryos of Astropecten aranciacus

Starfish have been instrumental in many fields of biological and ecological research. Oocytes of Astropecten aranciacus, a common species native to the Mediterranean Sea and the East Atlantic, have long been used as an experimental model to study meiotic maturation, fertilization, intracellular Ca2+ signaling, and cell cycle controls. However, investigation of the underlying molecular mechanisms has often been hampered by the overall lack of DNA or protein sequences for the species. In this study, we have assembled a transcriptome for this species from the oocytes, eggs, zygotes, and early embryos, which are known to have the highest RNA sequence complexity. Annotation of the transcriptome identified over 32,000 transcripts including the ones that encode 13 distinct cyclins and as many cyclin-dependent kinases (CDK), as well as the expected components of intracellular Ca2+ signaling toolkit. Although the mRNAs of cyclin and CDK families did not undergo significant abundance changes through the stages from oocyte to early embryo, as judged by real-time PCR, the transcript encoding Mos, a negative regulator of mitotic cell cycle, was drastically reduced during the period of rapid cleavages. Molecular phylogenetic analysis using the homologous amino acid sequences of cytochrome oxidase subunit I from A. aranciacus and 30 other starfish species indicated that Paxillosida, to which A. aranciacus belongs, is not likely to be the most basal order in Asteroidea. Taken together, the first transcriptome we assembled in this species is expected to enable us to perform comparative studies and to design gene-specific molecular tools with which to tackle long-standing biological questions

Phenotypic and genotypic characterization of imipenem-resistant Pseudomonas aeruginosa isolated in Buenos Aires

En el presente estudio, que tuvo por objeto analizar los mecanismos involucrados en la resistencia a carbapenemes, se incluyeron 129 aislamientos de Pseudomonas aeruginosa recuperados durante el año 2006 en el Hospital “Eva Perón” de la Provincia de Buenos Aires. La caracterización fenotípica y genotípica de la resistencia permitió reconocer la presencia de metalo-β-lactamasas (MBL) en el 14% de esos aislamientos. En todos ellos se identificó la presencia de la enzima IMP-13; sin embargo, algunos aislamientos resultaron sensibles a carbapenemes de acuerdo a los puntos de corte establecidos por el CLSI e incluso a las sugerencias de la Subcomisión de Antimicrobianos de SADEBAC, AAM. El ensayo de detección fenotípica de MBL de sinergia con doble disco resultó útil en este estudio. Sólo aquellos aislamientos productores de IMP-13 que a su vez presentaron alteraciones en las proteínas de membrana externa resultaron completamente resistentes a imipenem. Los aislamientos productores de MBL correspondieron a varios tipos clonales, lo cual sugiere no sólo la diseminación de una cepa resistente, sino también la diseminación horizontal de este mecanismo de resistencia entre clones diferentesrom 129 P. aeruginosa isolated at a health care centre located in Buenos Aires (Hospital “Eva Perón”), 14% produced IMP-13. Although 18 isolates were metallo-β-lactamases (MBL) producers, only those isolates that displayed altered outer membrane protein profiles correlated with the resistant category according to CLSI or even Subcomisión de Antimicrobianos, SADEBAC, AAM. Phenotypic screening of metallo-β-lactamases proved to be appropriate for detecting MBL producing isolates. IMP-13 producing isolates corresponded to at least five different clonal types, which not only suggests the dissemination of the resistant strain but also of the resistant marker.Fil: Cejas, D.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Almuzara, Marisa. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Santella, G.. Universidad de Buenos Aires; ArgentinaFil: Tuduri, A.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón". Servicio de Neurología; ArgentinaFil: Palombarani, Susana. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón"; ArgentinaFil: Figueroa, S.. Provincia de Buenos Aires. Ministerio de Salud. Hospital Interzonal de Agudos "Eva Perón". Servicio de Neurología; ArgentinaFil: Gutkind, Gabriel Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; ArgentinaFil: Radice, M.. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica; Argentin

Immunohistochemical quantitation of 4-aminobiphenyl-DNA adducts and p53 nuclear overexpression in T1 bladder cancer of smokers and nonsmokers

An immunoperoxidase method, using a monoclonal antibody which recognizes 4-aminobiphenyl (4-ABP)-DNA adducts, was developed for the detection and quantitation of DNA damage in bladder tissue and applied to stored paraffin blocks of transurethral resection specimens of 46 patients with T1 bladder cancer. Mean relative staining intensity for 4-ABP-DNA adducts was significantly higher in current smokers (275 \uc2\ub1 81, n = 24) compared to nonsmokers (113 \uc2\ub1 71, n = 22) (P < 0.0001). There was a linear relationship between mean levels of relative staining and number of cigarettes smoked with lower levels in the 1-19 cig./day group (205 \uc2\ub1 30, n = 5), compared to the 20-40 (289 \uc2\ub1 40, n = 7) and the > 40 cig./day group (351 \uc2\ub1 57, n = 3)(P < 0.001). Nuclear overexpression of p53, analyzed by immunoperoxidase staining, was observed in 27 (59%) of the 45 stage T1 tumors analyzed. There was a significant correlation between p53 overexpression and recurrence of disease (odds ratio = 12.3, P < 0.01). Nuclear staining of p53 was also correlated with smoking status, cig./day and 4-ABP-DNA adducts. This work demonstrates that the immunohistochemical method has sufficient sensitivity for detection of 4-ABP-DNA adducts in human bladder samples. The method has several advantages including small sample size, the possibility of retrospective analysis of stored paraffin blocks, the ability to analyze binding in specific cell types, and a relatively low cost