DSpace Angular :: Browsing by Author "Wozniak Banchero, Aniela"

Browsing by Author "Wozniak Banchero, Aniela"

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A multispecies outbreak of carbapenem-resistant bacteria harboring the blaKPC gene in a non-classical transposon element
(2021) Wozniak Banchero, Aniela; Figueroa, Cristian; Moya-Flores, Francisco; Guggiana, Piero; Castillo, Claudia; Rivas Jiménez, Lina María; Munita, José M.; García Cañete, Patricia
Abstract Background Klebsiella pneumoniae is the most frequent KPC-producing bacteria. The blaKPC gene is frequently embedded in Tn4401 transposon, and less frequently in non-Tn4401 elements (NTEKPC) variants I-III. The first case of KPC in the UC-CHRISTUS Clinical Hospital was detected in Pseudomonas aeruginosa. Soon after this event, KPC was detected in 2 additional Pseudomonas aeruginosa, 3 Escherichia coli, 3 Enterobacter cloacae, 3 Klebsiella pneumoniae, and 1 Citrobacter freundii, isolated from 6 different patients. We aimed to elucidate the possible mechanisms of genetic transfer and dissemination of the blaKPC gene among isolates of this multispecies outbreak. A molecular epidemiology analysis of the above mentioned clinical isolates (n = 13) through Multi-Locus Sequence Typing, plasmid analysis, Pulsed-Field Gel-Electrophoresis, and Whole-genome sequencing (WGS) was performed. Results High-risk sequence types were found: K. pneumoniae ST11, P. aeruginosa ST654, and E. cloacae ST114. All enterobacterial isolates were not clonal except for 3 E. coli isolated from the same patient. WGS analysis in 6 enterobacterial isolates showed that 4 of them had blaKPC embedded in a novel variant of NTEKPC designated NTEKPC-IIe. Upstream of blaKPC gene there was a 570 pb truncated blaTEM-1 gene followed by an insertion sequence that was 84% similar to ISEc63, a 4473 bp element of the Tn3 family. Downstream the blaKPC gene there was a truncated ISKpn6 gene, and the inverted repeat right sequence of Tn4401. The ISec63-like element together with the blaKPC gene plus Tn4401 remnants were inserted in the Tra operon involved in conjugative transfer of the plasmid. This NTE was carried in a broad host-range IncN plasmid. P. aeruginosa isolates carried blaKPC gene embedded in a typical Tn4401b transposon in a different plasmid, suggesting that there was no plasmid transfer between Enterobacteriaceae and P. aeruginosa as initially hypothesized. Conclusions Most enterobacterial isolates had blaKPC embedded in the same NTEKPC-IIe element, suggesting that this multispecies KPC outbreak was due to horizontal gene transfer rather than clonal spread. This poses a greater challenge to infection control measures often directed against containment of clonal spread.
A Novel Live Vector Group A Streptococcal emm Type 9 Vaccine Delivered Intranasally Protects Mice against Challenge Infection with emm Type 9 Group A Streptococci
(2014) Wozniak Banchero, Aniela; García Cañete, Patricia; Geoffroy, Enrique A.; Aguirre, Daniel B.; González, Samantha; Sarno, Victoria A.; Dale, James B.; Salazar Echegarai, Francisco Javier; Vera, Andrea Magdalena; Bueno Ramírez, Susan; Kalergis Parra, Alexis Mikes
A simple RNA preparation method for SARS-CoV-2 detection by RT-qPCR
(2020) Wozniak Banchero, Aniela; Cerda Rojas, Ariel Patricio; Lamig Giannini, Liliana Andrea; Solari Gajardo, Sandra; Guzmán Durán, Ana María; Riveras Hernández, Eleodoro Javier; Ferres Garrido, Marcela Viviana; Gutiérrez Ilabaca, Rodrigo Antonio; García Cañete, Patricia; Ibarra Henriquez, C.; Sebastian, V.; Armijo, G.; Lamig, L.; Miranda, C.; Lagos, M.; Quiroga, T.; Hitschfeld, S.
Antimicrobial susceptibility and genetic characteristics of Propionibacterium acnes isolated from patients with acne
(2013) Schafer, Fabiola; Fich, Félix; Lam, Marusella; Gárate, Cynthia; Wozniak Banchero, Aniela; García Cañete, Patricia
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.
Clinical and microbiological response of mice to intranasal inoculation with Lactococcus lactis expressing Group A Streptococcus antigens, to be used as an anti-streptococcal vaccine
(2018) García Cañete, Patricia; Paillavil, Braúlio A.; Scioscia, Natalia; Dale, James B.; Legarraga Raddatz, Paulette; Salazar Echegarai, Francisco Javier; Bueno Ramírez, Susan; Kalergis Parra, Alexis Mikes; Wozniak Banchero, Aniela
Comparison of manual and automated nucleic acid extraction methods from clinical specimens for microbial diagnosis purposes
(2016) Wozniak Banchero, Aniela; Geoffroy, Enrique; Miranda, Carolina; Castillo, Claudia; Sanhueza, Francia
Contamination rate of the surgical gowns during total hip arthroplasty
(2019) Klaber Rosenberg, Ianiv Walter; Ruiz, Pablo; Schweitzer Fernandez, Daniel Alberto; Lira Salas, María Jesús; Botello Correa, Eduardo Andrés; Wozniak Banchero, Aniela
Introduction: Surgical instrument contamination during total joint replacement is a matter of major concern. Available recommendations suggest changing suction tips, gloves and avoiding light handle manipulation during the procedure. There is a paucity of data regarding surgical gown contamination. The aim of the present study was to evaluate the contamination rate of surgical gowns (SGs) during total hip arthroplasty (THA) and secondarily compare it with other orthopedic procedures. Materials and methods: One hundred and forty surgical gowns (from 70 surgeries) were screened for bacterial contamination using thioglycolate (a high-sensitivity culture broth). The THA contamination rate was compared with those of knee and spine procedures. Controls were obtained at the beginning of every surgery and from the culture broth. The procedure’s duration and the level of training of the surgeon were evaluated as potential risk factors for contamination. Results: Bacterial contamination was identified on 12% of surgical gowns (22% of surgical procedures). The contamination rate during THA was 4.1% (2% in primary THA and 8.3% in revisions) vs 21.67% during other surgeries (spine and knee) (OR 6.15, p = 0.012). There were no contaminated SGs during THAs performed in ≤ 2 h (0/33 SGs) vs 7.5% (3/40) for THAs that took ≥ 2 h (p = 0.25). Conclusion: There was a high rate of SG contamination during orthopedic procedures that was higher during non-arthroplasty procedures and prolonged THAs. There were no contaminated surgical gowns in THAs under 120 min, efforts should point keeping primary THAs under this cutoff time. As a general recommendation, SGs should be changed every time there is concern about potential contamination. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.
Development of a robust FT-IR typing system for Salmonella enterica, enhancing performance through hierarchical classification
(American Society for Microbiology, 2025) Fredes García, Diego Antonio; Jiménez Rodríguez, Javiera Alejandra; Piña Iturbe, Luis Alejandro; Caballero Díaz, Pablo Ignacio; González Villarroel, Tamara Nicol; Dueñas, Fernando; Wozniak Banchero, Aniela; Adell, Aiko D.; Moreno Switt, Andrea Isabel; García Cañete, Patricia
Salmonella enterica is a leading cause of foodborne illnesses globally, with significant mortality rates, especially among vulnerable populations. Traditional serotyping methods for Salmonella are accurate but expensive, resource-intensive, and time-consuming, necessitating faster and more reliable alternatives. This study evaluates the IR Biotyper, a Fourier-transform infrared spectroscopy system, in differentiating Salmonella serovars. We assessed 458 isolates of nine Salmonella serovars (Infantis, Enteritidis, Typhimurium, I,4,[5],12:i:-, Montevideo, Agona, Thompson, Panama, and Abony) from diverse sources. The IR Biotyper was used to acquire spectra from these isolates. Machine learning algorithms, including support vector machines, were trained to classify the isolates. The accuracy of classifiers was validated using a validation set to determine sensitivity, specificity, positive predictive value, and negative predictive value. Initial classifiers showed high accuracy for Abony, Agona, Enteritidis, and Infantis serovars, with sensitivities close to 100%. However, classifiers for S. Typhimurium, S. Panama, and S. Montevideo exhibited lower performance. Implementing a hierarchical classification system enhanced the accuracy of serogroup O:4 serovars, demonstrating that this approach offers a robust framework for Salmonella serovar identification. The hierarchical system enables progressive refinement of classification, minimizing misclassifications by focusing on serogroup-specific features, making it adaptable to complex data sets and diverse serovars. The IR Biotyper demonstrates high potential for rapid and accurate Salmonella serovar identification. This study supports its implementation as a cost-effective, high-throughput tool for pathogen typing, enhancing real-time epidemiological surveillance, and guiding treatment strategies for salmonellosis. This method establishes a robust and scalable framework for advancing Salmonella serotyping practices across clinical, industrial, and public health domains by leveraging hierarchical classification.IMPORTANCEEarly and accurate identification of Salmonella serovars is extremely important for epidemiological surveillance, public health, and food safety. Traditional serotyping is very successful but is laborious and costly. In this study, we demonstrate the promise of Fourier-transform infrared spectroscopy together with machine learning as a means for Salmonella serotyping. Using hierarchical classification, we attain optimal serovar identification accuracy, particularly for challenging-to-type serogroups. Our findings recognize the IR Biotyper as a high-throughput, scalable pathogen typing solution that offers real-time data that can enable enhanced outbreak response and prevention of foodborne disease. The approach bridges the gap between traditional microbiological practice and sophisticated analytical technology, the path to more effective, cost-saving interventions in the clinical, industrial, and regulatory settings. Application of these technologies can significantly improve Salmonella surveillance-control and Public Health outcomes.
Development of an implantable three-dimensional model of a functional pathogenic multispecies biofilm to study infected wounds
(2022) Cárdenas Calderón, Camila Valentina; Veloso Giménez, Valentina del Carmen; González, Tamara; Wozniak Banchero, Aniela; García, Patricia; San Martín, Sebastián; Varas, Juan F.; Carrasco-Wong, Ivo; Vera, Mario; Egaña, José T.
Chronic wounds cannot heal due to impairment of regeneration, mainly caused by the persistent infection of multispecies biofilms. Still, the effects of biofilm wound infection and its interaction with the host are not fully described. We aimed to study functional biofilms in physiological conditions in vitro, and their potential effects in health and regeneration in vivo. Therefore, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus faecalis were seeded in collagen-based scaffolds for dermal regeneration. After 24 h, scaffolds had bacterial loads depending on the initial inoculum, containing viable biofilms with antibiotic tolerance. Afterwards, scaffolds were implanted onto full skin wounds in mice, together with daily supervision and antibiotic treatment. Although all mice survived their health was affected, displaying fever and weight loss. After ten days, histomorphology of scaffolds showed high heterogeneity in samples and within groups. Wounds were strongly, mildly, or not infected according to colony forming units, and P. aeruginosa had higher identification frequency. Biofilm infection induced leucocyte infiltration and elevated interferon-γ and interleukin-10 in scaffolds, increase of size and weight of spleen and high systemic pro-calcitonin concentrations. This functional and implantable 3D biofilm model allows to study host response during infection, providing a useful tool for infected wounds therapy development.
Diagnóstico de la infección por Treponema pallidum en pacientes con sífilis temprana y neurosífilis mediante reacción de la polimerasa en cadena
(2011) García Cañete, Patricia; Grassi Corrales, Bruno; Fich, Félix; Salvo Lizama, Aurelio Fernando; Araya, Luis; Abarzúa C., Fernando; Soto, Julia; Poggi, Helena; Lagos L., Marcela; Vásquez T., Patricia; Leon C., Eugenia; Pérez C., Carlos; Wozniak Banchero, Aniela
La sífilis es una enfermedad de transmisión sexual producida por Treponema pallidum, cuyo diagnóstico se realiza presuntivamente basándose en aspectos clínicos y análisis de especificidad limitada. La reacción de la polimerasa en cadena (RPC) ha sido planteada como una alternativa diagnóstica de mayor sensibilidad y especificidad. El objetivo de este trabajo fue validar una RPC para el diagnóstico de sífilis temprana (ST) y neurosífilis (NS). Se utilizaron muestras de lesiones muco-cutáneas y de LCR de pacientes con sospecha de cursar ST y NS respectivamente, previamente diagnosticados, utilizando un estándar de oro ampliado. La RPC fue realizada con partidores dirigidos al gen tpN47. De las 21 muestras de pacientes con ST, la RPC resultó positiva en 20, lo que resulta en una sensibilidad clínica de 95%. De las 8 muestras de pacientes con NS, la RPC resultó positiva en 4, obteniéndose una sensibilidad clínica de 50%. La especificidad clínica para ST y NS fue de 100%. La excelente sensibilidad y especificidad de la RPC para muestras muco-cutáneas permitió la exitosa implementación de este análisis en nuestro laboratorio para el diagnóstico de rutina. Si bien la sensibilidad de la RPC en LCR es baja, es muy útil para apoyar el diagnóstico clínico
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.
Effet de l’injection de Propionibacterium acnes (PA) sur la dégénérescence dans un modèle de rat
(2017) Zamora Helo, Tomás; Palma, J.; Andía Kohnenkampf, Marcelo Edgardo; García Cañete, Patricia; Wozniak Banchero, Aniela; Solar González, Antonieta Alejandra; Campos, M.
Etiologic and clinical characterization of community acquired gastroenteritis in adult patients in a Chilean emergency room by the FilmArray GI panel
(2018) Valenzuela Abarca, Eduardo; Legarraga Raddatz, Paulette; Peña Riveros, Arturo Nicolás; Arenas, Alex; Berkowitz Fiebich, Loni; Ramírez, Gigliola; Wozniak Banchero, Aniela; García Cañete, Patricia; Álvarez Lobos, Manuel
Evaluación de la técnica Xpert® MTB/RIF para la detección de Mycobacterium tuberculosis complex en muestras extra-pulmonares
(2017) García Cañete, Patricia; Balcells Marty, María Elvira; Castillo, C.; Miranda, C.; Geoffroy, E.; Roman, J.; Wozniak Banchero, Aniela
Evaluación de test rápidos y diseño de una estrategia para la detección y caracterización de carbapenemasas en cepas de bacilos gramnegativos
(2017) Muñoz, Constanza; Zumarán, Cecilia; González, Tamara; Wozniak Banchero, Aniela; Castillo, Claudia; García Cañete, Patricia
Evaluation of a rapid immunochromatographic test for detection of KPC in clinical isolates of Enterobacteriaceae and Pseudomonas species
(2019) Wozniak Banchero, Aniela; Paillavil, Braulio; Legarraga Raddatz, Paulette; Zumaran Bizuela, Cecilia; Prado, Sandra; García Cañete, Patricia
Evasion of Host Immunity by Virulent Salmonella: Implications for Vaccine Design
(2011) Riquelme Colet, Sebastián Alejandro; Wozniak Banchero, Aniela; Kalergis Parra, Alexis Mikes; Bueno Ramírez, Susan
Genomic Analysis of Carbapenem-Resistant Acinetobacter baumannii Strains Recovered from Chilean Hospitals Reveals Lineages Specific to South America and Multiple Routes for Acquisition of Antibiotic Resistance Genes
(2022) Brito, Barbara P.; Koong, Jonathan; Wozniak Banchero, Aniela; Opazo-Capurro, Andres; To, Joyce; Garcia, Patricia; Hamidian, Mehrad
Carbapenem-resistant Acinetobacter baumannii (CRAb) is a public health threat accounting for a significant number of hospital-acquired infections. Despite the importance of this pathogen, there is scarce literature on A. baumannii molecular epidemiology and evolutionary pathways relevant to resistance emergence in South American strains. We analyzed the genomic context of 34 CRAb isolates recovered from clinical samples between 2010 and 2013 from two hospitals in Santiago, Chile, using whole-genome sequencing. Several Institut Pasteur scheme sequence types (STs) were identified among the 34 genomes studied here, including ST1, ST15, ST79, ST162, and ST109. No ST2 (the most widespread sequence type) strain was detected. Chilean isolates were phylogenetically closely related, forming lineages specific to South America (e.g., ST1, ST79, and ST15). The genomic contexts of the resistance genes were diverse: while genes were present in a plasmid in ST15 strains, all genes were chromosomal in ST79 strains. Different variants of a small Rep_3 plasmid played a central role in the acquisition of the oxa58 carbapenem and aacC2 aminoglycoside resistance genes in ST1, ST15, and ST79 strains. The aacC2 gene along with blaTEM were found in a novel transposon named Tn6925 here. Variants of Tn7 were also found to play an important role in the acquisition of the aadA1 and dfrA1 genes. This work draws a detailed picture of the genetic context of antibiotic resistance genes in a set of carbapenem-resistant A. baumannii strains recovered from two Chilean hospitals and reveals a complex evolutionary picture of antibiotic resistance gene acquisition events via multiple routes involving several mobile genetic elements.
Human platelet interaction with E-coli O111 promotes tissue-factor-dependent procoagulant activity, involving Toll like receptor 4
(2017) Matus, V.; Valenzuela, J.; Hidalgo, P.; Pozo, L.; Panes Becerra, Olga Teresa; Wozniak Banchero, Aniela; Mezzano, Diego; Pereira Garcés, Jaime Ignacio; Sáez, Claudia G.

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