ABSTRACT Introduction: Carbapenem resistance in members of order Enterobacterales is a growing public health problem causing high mortality in developing and industrialized countries. Its emergence and rapid propagation worldwide was due to both intercontinental spread of pandemic strains and horizontal dissemination via mobile genetic elements (MGE) such as plasmids and transposons. Objective: To describe MGE carrying carbapenem resistance genes in Enterobacterales which have been reported in South America. Search strategy and selection criteria: A search of the literature in English or Spanish published until 2019 in PubMed, Google Scholar, LILACS and SciELO databases was performed for studies of MGE in Enterobacterales reported in South American countries. Results: Seven South American countries reported MGE related to carbapenemases. Carbapenemase-producing Klebsiella pneumoniae belonging to clonal complex 258 were the most prevalent pathogens reported; others carbapenemase-producing Enterobacterales such as Escherichia coli, Serratia marcescens, and Providencia rettgeri also have been reported. The MGE implicated in the spread of the most prevalent carbapenemase genes are Tn4401 and non-Tn4401 elements for bla KPC and ISAba125 for bla NDM, located in different plasmid incompatibility groups, i.e. L/M, A/C, FII and bacterial clones. Conclusion: This review indicates that, like in other parts of the world, the most commonly reported carbapenemases in Enterobacterales from South America are being disseminated through clones, plasmids, and transposons which have been previously reported in other parts of the world.

Transmission of leptospirosis is facilitated by the survival of pathogenic leptospires in moist environments outside their mammalian host. In the present study, the survival mechanisms of Leptospira interrogans serovar Canicola in aqueous conditions and lack of nutrients were investigated. In distilled water, leptospires were able to remain motile for 110 days (pH 7.2). However, when incubated in a semi-solid medium composed of distilled water and 0.5% purified agarose (pH 7.2), they survived 347 days. In this viscous environment, aggregates of live spirochetes were observed. Neither antibiotics (e.g. tetracycline and ampicillin) nor nutrients inhibited leptospiral aggregation. Immunoblot analysis suggested that cells incubated in water down-regulate the expression of LipL31, an inner-membrane protein, but retain expression of other membrane proteins. These studies provide insights into the mechanisms by which pathogenic Leptospira survives for prolonged periods of time in natural aqueous environments, a key stage in the leptospiral lifecycle.

A sobrevivência de Leptospira em ambientes úmidos, fora do mamífero hospedeiro, facilita a transmissão da enfermidade. Foi estudada a sobrevivência de Leptospira interrogans sorovar Canicola em meios aquosos carentes de nutrientes. As leptospiras em água destilada (pH 7,2) conservaram a mobilidade durante 110 dias. Quando foram incubadas em um meio semisólido, composto de água destilada adicionada de 0,5% de agarose purificado, as leptospiras sobreviveram 347 dias. Neste meio viscoso se observou que as leptospiras formam agregados. Nem a presença de nutrientes nem a de antibióticos (ampicilina ou tetraciclina) inibiu a agregação. A análise por imunotransferência indica que nas leptospiras incubadas em água há uma diminuição na expressão da proteína da membrana interna Lip L31, apesar de se conservar a expressão de outras proteínas da membrana. Este estudo proporciona uma visão dos mecanismos que permitem a sobrevivência das espécies patógenas de Leptospira em ambientes aquosos naturais, um processo importante no ciclo natural da leptospirose.

La supervivencia de Leptospira en ambientes húmedos, fuera del mamífero hospedador, facilita la transmisión de la enfermedad. Nosotros estudiamos la supervivencia de Leptospira interrogans serovar Canicola en medios acuosos carentes de nutrientes. En agua destilada (pH 7,2), las leptospiras conservaron la movilidad durante 110 días. Sin embargo, cuando se incubaron en un medio semisólido, compuesto de agua destilada y 0,5% de agarosa purificada, sobrevivieron 347 días. En este medio viscoso se observó que las leptospiras formaban agregados. Ni la presencia de nutrientes ni la de antibióticos (ampicilina o tetraciclina) inhibieron la agregación. El análisis por inmunotransferencia indica que en las leptospiras incubadas en agua disminuye la expresión de la proteína de membrana interna LipL31; no obstante, conservan la expresión de otras proteínas de membrana. Este estudio proporciona una visión de los mecanismos que permiten la supervivencia de las especies patógenas de Leptospira en ambientes acuáticos naturales, un proceso importante en el ciclo natural de la leptospirosis.

The contact with polluted waters is one of the main risk factors to catch leptospirosis. A study is presented about the adaptation of Leptospira interrograns to nutrient-lacking water media. For this end, leptospires were incubated in distilled water and tampon saline solution for an undetermined period of time. Leptospires kept viable in water for 98 days whereas the incubated ones in tampon saline solution survived 3 weeks only. Protein cellular and external membrane components were analyzed with electrophoresis in acrylamide gel (SDS-PAGE). When OM protein profiles of leptospires kept in water were compared to those OM profiles of cells cultured in ENJA medium, some differences were observed. A 56 kDa protein was present in leptospires kept in water for a week. This protein was identified as GroEL through Western Blot test.

Se describió un estudio acerca de la adaptación de Leptospira interrogans a medios acuosos carentes de nutrientes. Para este propósito se incubaron leptospiras por período de tiempo indeterminado en agua destilada y en solución salina tamponada. Las leptospiras se mantuvieron viables en agua por 98 d, mientras que, las incubadas en solución salina tamponada sobrevivieron únicamente 3 semanas. Los componentes proteicos celulares y de membrana externa fueron analizados mediante electroforesis en geles de acrilamida (SDS-PAGE). Cuando se compararon los perfiles de proteínas de OM de leptospiras mantenidas en agua, con aquellos perfiles de OM de células cultivadas en medio EMJH, se observaron algunas diferencias. Una proteína de 56 kDa estuvo presente en leptospiras que fueron mantenidas en agua por una semana. Mediante análisis de western blot se identificó a esta proteína como GroEL.