Evaluation of the Blue-Carba test for rapid detection of carbapenemases in gram-negative Bacilli

The Blue-Carba test (BCT) is a biochemical test for rapid (2 h)detection of carbapenemase production in Gram-negative bacillidirectly from bacterial culture . It is based on the in vitrohydrolysis of imipenem by bacterial colonies (direct inoculationwithout prior lysis), which is detected by changes in pH valuesrevealed by the indicator bromothymol blue (blue to green/yellowor green to yellow). It was reported to be 100% sensitive andspecific for Enterobacteriaceae, Pseudomonasspp., and Acinetobacterspp. harboring carbapenemases . We evaluated a simplifiedprotocol of the BCT against various Gram-negative species, includingcombinations of bacterial species/resistance mechanismsthat were not previously evaluated.Fil: Pasteran, Fernando. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Veliz, Omar. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Ceriana, Paola. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Lucero, María Celeste. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Rapoport, Melina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Albornoz, Ezequiel Pablo. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Gómez, Sonia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; ArgentinaFil: Corso, Alejandra. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”; Argentin

Microeconomic adjustments during an export boom: Argentina, 2003-11

This paper examines Argentine exports at the firm level between 2003 and 2011, a period of exceptional and sustained export growth. While at the product level, the pattern of specialisation barely changed, exporters exhibit new dynamics in international markets: firms not only expanded sales abroad by increasing their exports in existing markets, but also by entering into new destinations and adding new products. That is, new export strategies allowed exporters achieve greater resistance to the variations in the macroeconomic environment. We find that the importance of the different export margins changes overtime: while the currency is depreciated, the intensive margin explains most of export growth, whereas the subextensive and extensive margins become the main source of export growth once the currency appreciates. We also uncover a strong complementarity between import and export growth

Universal Critical Exponents of the Magnetic Domain Wall Depinning Transition

Magnetic field driven domain wall dynamics in a ferrimagnetic GdFeCo thin film with perpendicular magnetic anisotropy is studied using low temperature magneto-optical Kerr microscopy. Measurements performed in a practically athermal condition allow for the direct experimental determination of the velocity ($\beta = 0.30 \pm 0.03$) and correlation length ($\nu = 1.3 \pm 0.3$) exponents of the depinning transition. The whole family of exponents characterizing the transition is deduced, providing evidence that the depinning of magnetic domain walls is better described by the quenched Edwards-Wilkinson universality class.Comment: 6 pages, 3 figures. Ancillary Material with 10 pages and 4 figures is also include

Degradation and mineralization of erythromycin by heterogeneous photocatalysis using SnO2-doped TiO2 structured catalysts: Activity and stability

Heterogeneous photocatalysis was used for the degradation and mineralization of erythromycin (ERY), with a consequent production of carboxylic acids. For that, a series of TiO2 and Ti1-xSnxO2 structured catalysts, namely M1 to M5, was prepared using the washcoating method, with the catalytic coatings being deposited onto stainless steel meshes. Besides, the catalytic activity of the prepared systems was compared to that of the commercial mesh (CM). The results showed that the prepared TiO2 structured catalyst (M1) presented better ERY oxidation than the CM one, what was associated to the higher catalyst load and to the anatase/rutile ratio. Considering the Sn-doped structured catalysts, for M2, M4 and M5 catalysts, lower ERY mineralization and high formation of carboxylic acids were found, when compared to the M3 catalyst. The improved M3 activity was attributed to the formation of a staggered gap (type II heterojunction), providing better charge separation. In this situation, a high generation of hydroxyl radicals is obtained, resulting on a higher ERY mineralization. By the obtained results it is possible to determine that the addition order and the type of Sn compound added in the washcoating process, affects the catalytic activity due to the formation of a solid solution and to the type of produced heterostructures. The M3 catalyst also showed high stability in long-term tests up to 44 h of reaction. The results provide insights into the development of an inexpensive structured catalyst production method and its influence in the stability of the photocatalyst, as well as in its applicability on water/wastewater treatment.Fil: Albornoz, L.L. Universidade Federal do Rio Grande do Sul; BrasilFil: da Silva, S.W.. Universidade Federal do Rio Grande do Sul; BrasilFil: Bortolozzi, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Banus, Ezequiel David. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Brussino, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Ulla, Maria Alicia del H.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera". Universidad Nacional del Litoral. Instituto de Investigaciones en Catálisis y Petroquímica "Ing. José Miguel Parera"; ArgentinaFil: Bernardes, Andrea Moura. Universidade Federal do Rio Grande do Sul; Brasi

Characterization of a multidrug resistant Citrobacter amalonaticus clinical isolate harboring blaNDM-1 and mcr-1.5 genes

A multidrug resistant isolate, identified as Citrobacter amalonaticus using MALDI-TOF MS and confirmed by genomic analysis, was recovered from a pediatric patient in a hospital from Buenos Aires, Argentina. By whole-genome sequencing a total of 16 resistance genes were detected, including blaNDM-1 and mcr-1.5. To the best of our knowledge this is the first description of these two genes together in a clinical isolate of the Citrobacter genus.Fil: Faccone, Diego Francisco. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; ArgentinaFil: Albornoz, Ezequiel Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; ArgentinaFil: Tijet, Nathalie. Public Health Ontario; CanadáFil: Biondi, Estefania. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Gómez, Sonia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; ArgentinaFil: Pasteran, Fernando. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; ArgentinaFil: Vazquez, Miryam. Gobierno de la Ciudad de Buenos Aires. Hospital General de Niños "Ricardo Gutiérrez"; ArgentinaFil: Melano, Roberto Gustavo. University of Toronto; Canadá. Public Health Ontario; CanadáFil: Corso, Alejandra. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; Argentin

Differential distribution of plasmid-mediated quinolone resistance genes in clinical enterobacteria with unusual phenotypes of quinolone susceptibility from Argentina

We studied a collection of 105 clinical enterobacteria with unusual phenotypes of quinolone susceptibility to analyze the occurrence of plasmid-mediated quinolone resistance (PMQR) and oqx genes and their implications for quinolone susceptibility. The oqxA and oqxB genes were found in 31/34 (91%) Klebsiella pneumoniae and 1/3 Klebsiella oxytoca isolates. However, the oqxA- and oqxB-harboring isolates lacking other known quinolone resistance determinants showed wide ranges of susceptibility to nalidixic acid and ciprofloxacin. Sixty of the 105 isolates (57%) harbored at least one PMQR gene [qnrB19, qnrB10, qnrB2, qnrB1, qnrS1, or aac(6′)-Ib-cr)], belong to 8 enterobacterial species, and were disseminated throughout the country, and most of them were categorized as susceptible by the current clinical quinolone susceptibility breakpoints. We developed a disk diffusion-based method to improve the phenotypic detection of aac(6′)-Ib-cr. The most common PMQR genes in our collection [qnrB19, qnrB10, and aac(6′)-Ib-cr] were differentially distributed among enterobacterial species, and two different epidemiological settings were evident. First, the species associated with community-acquired infections (Salmonella spp. and Escherichia coli) mainly harbored qnrB19 (a unique PMQR gene) located in small ColE1-type plasmids that might constitute its natural reservoirs. qnrB19 was not associated with an extended-spectrum β-lactamase phenotype. Second, the species associated with hospital-acquired infections (Enterobacter spp., Klebsiella spp., and Serratia marcescens) mainly harbored qnrB10 in ISCR1-containing class 1 integrons that may also have aac(6′)-Ib-cr as a cassette within the variable region. These two PMQR genes were strongly associated with an extended-spectrum β-lactamase phenotype. Therefore, this differential distribution of PMQR genes is strongly influenced by their linkage or lack of linkage to integrons.Fil: Andrés, Patricia. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Area de Antimicrobianos; ArgentinaFil: Lucero, Celeste. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Area de Antimicrobianos; ArgentinaFil: Soler Bistue, Alfonso Jc. Fundación Instituto Leloir; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Guerriero, Leonor. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Area de Antimicrobianos; ArgentinaFil: Albornoz, Ezequiel Pablo. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Area de Antimicrobianos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tran, Tung. California State University; Estados UnidosFil: Zorreguieta, Ángeles. Fundación Instituto Leloir; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: PMQR Group. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Area de Antimicrobianos; ArgentinaFil: Galas, Marcelo Fabián. Dirección Nacional de Instituto de Investigación. Adm.nacional de Laboratorio E Instituto de Salud "dr.c.g.malbran". Instituto Nacional de Enfermedades Infecciosas. Departamento de Bacteriologia; ArgentinaFil: Corso, Alejandra. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Area de Antimicrobianos; ArgentinaFil: Tolmasky, Marcelo. California State University; Estados UnidosFil: Petroni, Alejandro. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Area de Antimicrobianos; Argentin

Emergence of genetically unrelated NDM-1-producing Acinetobacter pittii strains in Paraguay

The New Delhi metallo-β-lactamase (NDM-1) was initially identified in Escherichia coli and Klebsiella pneumoniae isolates in Sweden, from a patient previously hospitalized in India.1 To date, NDM producers in Latin America have been scarce, and associated with species of Enterobacteriaceae from Guatemala, Mexico, Colombia and Brazil, although in Honduras it was reported in Acinetobacter baumannii.2?6 Here, we report two genetically unrelated NDM-1-producing Acinetobacter pittii isolates identified in Paraguay. Since 1996, the Pan American Health Organization (PAHO) has supported a regional surveillance system, the Antimicrobial Resistance Surveillance Network in Latin America (ReLAVRA), that includes 794 laboratories from 20 Latin American countries, including their respective reference laboratories.7 This network provides reliable, timely and reproducible microbiological data in order to improve patient care. A regional protocol for the detection of carbapenemases has been harmonized and implemented through ReLAVRA. Briefly, metallo-β-lactamase (MBL) production is suspected in isolates that exhibit decreased susceptibility to carbapenems (CLSI criteria) and a positive synergy test result between a disc containing 10 μg of imipenem and a disc containing 750 μg of EDTA plus 1900 μg of sodium thioglycolate.8 During 2012, following the ReLAVRA algorithm, the National Health Laboratory of Paraguay confirmed an MBL phenotype in two Acinetobacter spp. isolates recovered from a single hospital. This phenotype had not previously been observed in Acinetobacter spp. from Paraguay.Fil: Pasteran, Fernando. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; ArgentinaFil: Martinez Mora, Mario. Laboratorio Central de Salud Pública. Servicio Antimicrobianos; ParaguayFil: Albornoz, Ezequiel Pablo. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Faccone, Diego Francisco. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Franco, Rossana. Laboratorio Central de Salud Pública. Servicio Antimicrobianos; ParaguayFil: Ortellado, Juana. Universidad Nacional de Asunción; ParaguayFil: Melgarejo, Nancy. Laboratorio Central de Salud Pública. Servicio Antimicrobianos; ParaguayFil: Gómez, Sonia Alejandra. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Riquelme, Irma. Universidad Nacional de Asunción; ParaguayFil: Matheu, Jorge. Pan American Health Organization. Antimicrobial Resistance and Infection Control Program; Estados UnidosFil: Ramon Pardo, Jorge Matheu Pilar. Pan American Health Organization. Antimicrobial Resistance and Infection Control Program; Estados UnidosFil: Corso, Alejandra. Dirección Nacional de Institutos de Investigación. Administración Nacional de Laboratorios e Institutos de Salud. Instituto Nacional de Enfermedades Infecciosas. Área de Antimicrobianos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Resistance to colistin mediated by the mcr-1 gene identified in strains of Escherichia coli and Klebsiella pneumoniae. First reports in Peru

Introducción. Ante la aparición de reportes de la presencia del gen mcr-1 y su posible diseminación por plásmidos en los países de la región y dado que este gen confiere resistencia a colistín, fármaco que es la última línea de tratamiento  contra bacterias multirresistentes, es importante conocer su presencia en nuestro país en microorganismos que lo expresen. Métodos. Se realizó un estudio descriptivo y transversal. Se incluyeron microorganismos aislados de urocultivos de pacientes ambulatorios de un centro de salud privado en Lima, Perú, en agosto del año 2017. De 326 urocultivos positivos se seleccionaron 10 aislamientos entre cepas de Escherichia coli y Klebsiella pneumoniae que presentaron concentración mínima inhibitoria ≥4μg/mL (interpretado como resistente para colistín) por el sistema automatizado Microscan Walkaway 96 plus. Se utilizaron los siguientes métodos: colistín agar spot, predifusión con tabletas de colistín, microdilución en caldo colistin y PCR para el gen mcr-1. Resultados. Se determinó que 7 aislamientos, todas Escherichia coli, expresaron la presencia del gen mcr-1 por PCR, el cual confiere resistencia plasmídica a polipéptidos. De las cepas restantes, dos Escherichia coli y una Klebsiella pneumoniae, resultaron positivos para resistencia a colistín en las pruebas fenotípicas pero no en la PCR para gen mcr-1 lo cual sugiere un mecanismo de resistencia a colistín no asociado a gen mcr-1. Conclusiones. Se obtuvieron 7 aislamientos de Escherichia coli resistentes a colistín y con expresión del gen mcr-1.Introduction. Given the appearance of reports of the presence of the mcr-1 gene and its possible dissemination by plasmids in the countries of the region and given that this gene confers resistance to colistin, the drug that is the last line of treatment against multiresistant bacteria, it is important to know its presence in our country in microorganisms that express it. Methods. Descriptive and cross-sectional study was carried out. Microorganisms isolated from urine culture of outpatients from a private health center in Lima, Peru, were included in august 2017. Out of 326 positive urine cultures, 10 isolates were selected between strains of Escherichia coli and Klebsiella pneumoniae that had a minimum inhibitory concentration ≥4μg/mL (interpreted as resistant for colistín) by the automated system Microscan Walkaway 96 plus. The following methods were used: colistin agar spot, prediffusion with colistin tablets, microdilution in colistin broth and PCR for the mcr-1 gene. Results. It was determined that 7 isolates, all Escherichia coli, expressed the presence of the mcr-1 gene by PCR, which confers plasmid resistance to polypeptides. Of the remaining strains, two Escherichia coli and one Klebsiella pneumoniae, were positive for resistance to colistin in the phenotypic tests but not in the PCR for mcr-1 gene, which suggests a mechanism of colistin resistance not associated with the mcr-1 gene. Conclusions. Seven isolates of Escherichia coli resistant to colistin and with expression of the mcr-1 gene were obtained

A New Twist: The Combination of Sulbactam/Avibactam Enhances Sulbactam Activity against Carbapenem-Resistant

An increasing number of untreatable infections are recorded every year. Many studies have focused their efforts on developing new β-lactamase inhibitors to treat multi-drug resistant (MDR) isolates. In the present study, sulbactam/avibactam and sulbactam/relebactam combination were tested against 187 multi-drug resistant (MDR) Acinetobacter clinical isolates; both sulbactam/avibactam and sulbactam/relebactam restored sulbactam activity. A decrease ≥2 dilutions in sulbactam MICs was observed in 89% of the isolates when tested in combination with avibactam. Sulbactam/relebactam was able to restore sulbactam susceptibility in 40% of the isolates. In addition, the susceptibility testing using twenty-three A. baumannii AB5075 knockout strains revealed potential sulbactam and/or sulbactam/avibactam target genes. We observed that diazabicyclooctanes (DBOs) β-lactamase inhibitors combined with sulbactam restore sulbactam susceptibility against carbapenem-resistant Acinetobacter clinical isolates. However, relebactam was not as effective as avibactam when combined with sulbactam. Exploring novel combinations may offer new options to treat Acinetobacter spp. infections, especially for widespread oxacillinases and metallo-β-lactamases (MBLs) producers

Emergence of NDM-1-producing Klebsiella pneumoniae in Guatemala

Fil: Pasteran, Fernando. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Albornoz, Ezequiel. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Faccone, Diego. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Gómez, Sonia. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Valenzuela, Claudia. Unidad Central de Referencia para la Vigilancia Epidemiológica. Laboratorio Nacional de Salud. Sección Bacteriología; Guatemala.Fil: Morales, Melissa. Unidad Central de Referencia para la Vigilancia Epidemiológica. Laboratorio Nacional de Salud. Sección Bacteriología; Guatemala.Fil: Estrada, Pavela. Hospital Infantil de Infectología y Rehabilitación; Guatemala.Fil: Valenzuela, Laura. Hospital General San Juan de Dios; Ciudad de Guatemala.Fil: Matheu, Jorge. Pan American Health Organization/World Health Organization. Alert and Response and Epidemic Diseases; Estados Unidos.Fil: Guerriero, Leonor. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina.Fil: Arbizú, Enrique. Unidad Central de Referencia para la Vigilancia Epidemiológica. Laboratorio Nacional de Salud. Sección Bacteriología; Guatemala.Fil: Calderón, Yeraldine. Unidad Central de Referencia para la Vigilancia Epidemiológica. Laboratorio Nacional de Salud. Sección Bacteriología; Guatemala.Fil: Ramon-Pardo, Pilar. Pan American Health Organization/World Health Organization. Alert and Response and Epidemic Diseases; Estados Unidos.Fil: Corso, Alejandra. ANLIS Dr.C.G.Malbrán. Instituto Nacional de Enfermedades Infecciosas; Argentina