Browsing by Author "Pallares, Christian"
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Item Detection of carbapenemase-producing Pseudomonas aeruginosa: Evaluation of the carbapenem inactivation method (CIM)(Elsevier Doyma, 2019-03-18) Gutiérrez, Sergio; Correa, Adriana; Hernández Gómez, Cristhian; De La Cadena, Elsa; Pallares, Christian; Villegas, María VirginiaIntroduction: The carbapenem inactivation method (CIM) is a cost-effective assay for detecting carbapenemases. However, its interpretation is unclear for Pseudomonas spp. We evaluate its accuracy when meropenem is changed to imipenem. Methods: We analyzed 266 P. aeruginosa isolates. The CIM method consists of: resuspend bacterial colonies (a full 10 μL loop) in 400 μL water, in which a 10 μg disk of meropenem/imipenem is immersed. After 2 h of incubation (35 °C), remove the disk, place it onto a Mueller-Hinton agar plate previously inoculated with Escherichia coli (ATCC 25922), and incubate at 35 ̊C between 18-24 h. Interpretation criteria (mm of inhibition zone): ≤19 mm, positive; ≥25 mm negative; 20–24 mm, undetermined. Results: Imipenem improves the sensitivity and specificity of CIM when compared to meropenem (99.4% and 98.9%, vs. 91.9% and 94.7%, respectively). Conclusions: The accuracy of CIM for carbapenemase detection in P. aeruginosa is increased with the use of imipenem.Item Genetic Diversity of Multidrug-Resistant Pseudomonas aeruginosa Isolates Carrying blaVIM–2 and blaKPC–2 Genes That Spread on Different Genetic Environment in Colombia(2021) Rada, Ana M.; De La Cadena, Elsa; Agudelo, Carlos A.; Pallares, Christian; Restrepo, Eliana; Correa, Adriana; Villegas, María V.; Capataz, CesarPseudomonas aeruginosa is an opportunistic Gram-negative pathogen with an increase in the frequency of infections caused by multidrug resistant (MDR) and extensively drug resistant (XDR) strains, limiting the available therapeutic options. The most troublesome resistance is the acquisition and production of carbapenemases such as Verona integron-encoded metallo-β-lactamases (VIM), the most frequent and widespread, and the Klebsiella pneumoniae carbapenemases (KPC), which has continuously spread in the last decade. Its dissemination is linked to their location on mobile genetic elements (MGEs). In Colombia, VIM and KPC have been increasing in its frequency showing major successful dissemination. In this article, we molecularly characterized and analyzed the genetic context of blaVIM and blaKPC in carbapenem-resistant P. aeruginosa (CRPA) isolates from infected and colonized patients in two tertiary-care hospitals, one in Medellín and the other in a municipality close to Medellín, both areas with high carbapenemase endemicity in Colombia (2013–2015). Using whole-genome sequencing (WGS), we identified a remarkable variety of genetic backgrounds in these MDR P. aeruginosa isolates carrying blaKPC–2 and blaVIM–2. There were a diversity of class 1 integron and variations in the gene cassettes associated to blaVIM–2, as well as a possible event of spread of blaKPC–2 mediated by a plasmid that contained part of Tn4401b in one infection case. The dissemination of blaVIM–2 and blaKPC–2 in P. aeruginosa in this area in Colombia has been strongly influenced by successful international clones, carrying these genes and additional determinants of resistance on MGEs, accompanied by gene rearrangement under an antimicrobial selection pressure. These findings emphasize the need to implement control strategies based on rational antibiotic useItem Impact of antimicrobial stewardship programs on antibiotic consumption and antimicrobial resistance in four Colombian healthcare institutions(2022-12) Pallares, Christian; Hernández Gómez, Cristhian; Appel, Tobías Manuel; Escandón, Kevin; Reyes, Sergio; Salcedo, Soraya; Matta, Lorena; Martínez, Ernesto; Cobo, Sara; Mora, Laura; Marín, Adriana; Correa, Adriana; De La Cadena, Elsa; Rodríguez Baño, Jesús; Villegas, María VirginiaBackground Antimicrobial stewardship programs (ASPs) have become a fundamental pillar in optimizing antimicrobial usage, improving patient care, and reducing antimicrobial resistance (AMR). Herein we evaluated the impact of an ASP on antimicrobial consumption and AMR in Colombia. Methods We designed a retrospective observational study and measured trends in antibiotic consumption and AMR before and after the implementation of an ASP using interrupted time series analysis over a 4-year period (24 months before and 24 months after ASP implementation). Results ASPs were implemented according to the available resources in each of the institutions. Before ASP implementation, there was a trend toward an increase in the antibiotic consumption of all measured antimicrobials selected. Afterward, an overall decrease in antibiotic consumption was observed. The use of ertapenem and meropenem decreased in hospital wards, while a decrease in the use of ceftriaxone, cefepime, piperacillin/tazobactam, meropenem, and vancomycin was observed in intensive care units. After ASP implementation, the trend toward an increase of oxacillin-resistant Staphylococcus aureus, ceftriaxone-resistant Escherichia coli, and meropenem-resistant Pseudomonas aeruginosa was reversed. Conclusions In our study, we showed that ASPs are a key strategy in tackling the emerging threat of AMR and have a positive impact on antibiotic consumption and resistance.