Browsing by Author "Wozniak Banchero, Aniela"

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    Chromosome-Mediated Colistin Resistance in Clinical Isolates of Klebsiella pneumoniae and Escherichia coli: Mutation Analysis in the Light of Genetic Background
    (Dove Medical Press Ltd, 2023) Riquelme, María Paz; Martínez, Rodrigo W.; Brito, Bárbara; García, Patricia; Wozniak Banchero, Aniela; Legarraga, Paulette
    © 2023 Riquelme et al.Purpose: Colistin resistance mechanisms involving mutations in chromosomal genes associated with LPS modification are not completely understood. Mutations in genes coding for the MgrB regulator frequently account for colistin resistance in Klebsiella pneumoniae, whereas mutations in genes coding for PhoPQ and PmrAB are frequent in E. coli. Our aim was to perform a genetic analysis of chromosomal mutations in colistin-resistant (MIC ≥4 µg/mL) clinical isolates of K. pneumoniae (n = 8) and E. coli (n = 7) of different STs. Methods: Isolates were obtained in a 3-year period in a university hospital in Santiago, Chile. Susceptibility to colistin, aminoglyco-sides, cephalosporins, carbapenems and ciprofloxacin was determined through broth microdilution. Whole genome sequencing was performed for all isolates and chromosomal gene sequences were compared with sequences of colistin-susceptible isolates of the same sequence types. Results: None of the isolates carried mcr genes. Most of the isolates were susceptible to all the antibiotics analyzed. E. coli isolates were ST69, ST127, ST59, ST131 and ST14, and K. pneumoniae isolates were ST454, ST45, ST6293, ST380 and ST25. All the isolates had mutations in chromosomal genes analyzed. K. pneumoniae had mutations mainly in mgrB gene, whereas E. coli had mutations in pmrA, pmrB and pmrE genes. Most of the amino acid changes in LPS-modifying enzymes of colistin-resistant isolates were found in colistin-susceptible isolates of the same and/or different ST. Eleven of them were found only in colistin-resistant isolates. Conclusion: Colistin resistance mechanisms depend on genetic background, and are due to chromosomal mutations, which implies a lower risk of transmission than plasmid-mediated genes. Colistin resistance is not associated with multidrug-resistance, nor to high-risk sequence types.
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    Effect of Propionibacterium acnes (PA) injection on intervertebral disc degeneration in a rat model : does it mimic modic changes?
    (2017) Zamora Helo, Tomás; Palma, J.; Andía Kohnenkampf, Marcelo Edgardo; García Cañete, Patricia; Wozniak Banchero, Aniela; Solar González, Antonieta Alejandra; Campos, M.
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    Primera comunicación en Chile de la detección del gen mcr-1 en un aislado clínico
    (Sociedad Chilena de Infectologia, 2018) Legarraga Raddatz, Paulette; Wozniak Banchero, Aniela; Garcia Canete, Patricia Del Carmen; Prado Stuardo, Sandra Antonia; Estrella Cedeno, Laura Estefania
    © 2018, Sociedad Chilena de Infectologia. All rights reserved.Recently it was described the plasmidial gene mcr-1 associated with colistin resistance. We screened by PCR and sequencing for gene mcr-1 in thirteen clinical isolates resistant to colistin. We observed amplification in one E. coli. To our knowledge, this is the first report of the presence of mcr-1 gene in Chile.
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    Salmonella pathogenicity island 1 differentially modulates bacterial entry to dendritic and non-phagocytic cells
    (2010) Bueno Ramírez, Susan; Wozniak Banchero, Aniela; Leiva, Eduardo D.; Riquelme Colet, Sebastián Alejandro; Carreño Márquez, Leandro Javier; Hardt, Wolf Dietrich; Riedel, Claudia A.; Kalergis Parra, Alexis Mikes
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    Vigilancia de enterobacterias productoras de carbapenemasas en cultivos rectales en un hospital universitario de Santiago, Chile
    (2013) Gutiérrez, Catalina; Labarca L., Jaime; Román, Juan C.; Sanhueza, Francia; Moraga, Marcela; Wozniak Banchero, Aniela; García Cañete, Patricia