Publications by authors named "Melina L Ferreira"

Article Synopsis
  • The study investigates antibiotic prescribing practices in adult ICUs across Brazil to address the issues related to multidrug-resistant infections in low- and middle-income countries.* -
  • A survey conducted in 58 ICUs found that 63.9% of the 620 patients were on antibiotics, with 72.3% receiving empirical treatment, indicating a lack of reliance on microbiological testing.* -
  • The findings show a high incidence of pneumonia and bloodstream infections, with significant variations in antibiotic use between teaching and non-teaching hospitals, raising concerns about healthcare-associated infections.*
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Introduction: Multi-drug-resistant (MDR) Pseudomonas aeruginosa is a dangerous pathogen causing nosocomial infection, particularly in low- and middle-income countries like Brazil. This retrospective study at a Brazilian university hospital examined the relationship between antimicrobial use and MDR-P. aeruginosa.

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Article Synopsis
  • * Whole-genome sequencing revealed that 85% of isolates belonged to clonal complex 258, with varying resistance levels to polymyxin B, and identified significant mutations linked to resistance.
  • * Quantitative real-time PCR showed significant overexpression of specific resistance-related genes in polymyxin B-resistant isolates, indicating genetic diversity and potential unknown mechanisms of resistance among these strains.
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. Carbapenem-resistant is responsible for increased patient mortality. Five and 30 day in-hospital all-cause mortality in patients with infections were assessed, followed by evaluations concerning potential correlations between the type III secretion system (TTSS) genotype and the production of metallo-β-lactamase (MBL).

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This study used whole-genome sequencing (WGS) and PFGE to analysis KPC-2-producing Klebsiella pneumoniae strains from clinical specimens collected in Brazilian hospitals. The study identifies the emergence of a novel small IncX3 plasmid (pKPB11), 12,757-bp in length, in a high-risk K. pneumoniae ST11/CG258 lineage, a successful clonal group in Brazil, carrying the bla gene on a non-Tn4401 genetic element (NTE-Ic).

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Background: Carbapenem-resistant Acinetobacter baumannii (CR-Ab) has become a worrying health care problem, mainly in developing countries, such as Brazil. The objective was to investigate the prevalence and prognostic factors for CR-Ab infections at a Brazilian university hospital and examine the impact of inappropriate antimicrobial therapy on patient outcome.

Methods: A retrospective study on hospitalized patients with CR-Ab infections was carried out from January 2013 to December 2017.

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The dissemination of antimicrobial resistance genes and the bacterium that harbor them have increasingly become a public concern, especially in low- and middle-income countries. The present study used whole-genome sequencing to analyze 10 KPC-2-producing isolates obtained from clinical specimens originated from Brazilian hospitals. The study documents a relevant "snapshot" of the presence of class 1 integrons in 90% of the strains presenting different gene cassettes ( and ), associated or not with transposons.

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The emergence of infections associated to new antimicrobial resistance in Acinetobacter baumannii (Ab) genotypes represents a major challenge. In this context, this study aimed to determine the diversity of resistance mechanisms and investigate clonal dissemination and predominant sequence types (STs) in multidrug-resistant Ab strains of clinical (tracheal aspirate, n = 17) and environmental (surface, n = 6) origins. Additionally, the major clones found in clinical (A) and environmental (H) strains had their complete genomes sequenced.

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Carbapenemase-producing organisms are pandemic and a significant threat to public health. We investigated the clonal relatedness of colistin-resistant strains producing KPC-type carbapenemase (KPC-KP) causing subsequent infections or colonization. Moreover, we aimed to gain insight into the ability of biofilm production in strains producing carbapenemase.

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Article Synopsis
  • - This study investigates the presence of virulence genes in Klebsiella pneumoniae (KPC-KP) using whole-genome sequencing, highlighting the frequency of hypervirulent and hypermucoviscous strains.
  • - It finds that most strains of KPC-KP are capable of forming biofilms, with 90.9% showing this ability, particularly focusing on the international clonal group 258 (CG258).
  • - The research identifies a link between sequence type ST437 and lower biofilm production, indicating that KPC-KP with multiple virulence traits is spreading in Brazilian hospitals, contributing to infection rates.
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  • The study investigated quinolone resistance in 40 fluoroquinolone-resistant isolates from both hospital and community settings, focusing on plasmid-mediated quinolone resistance (PMQR) and specific gene mutations.
  • Key mutations were found in the QRDRs, and two new nucleotide substitutions were identified in the studied genes.
  • The results indicated a higher prevalence of PMQR genes in community isolates and highlighted the need for increased surveillance of community-acquired infections due to their potential role in spreading antibiotic resistance.
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  • A retrospective study analyzed the factors contributing to bacteremia caused by multidrug-resistant and extensively drug-resistant Pseudomonas aeruginosa, focusing on overexpressed efflux pumps and changes in porin structures.
  • Molecular techniques like Pulsed Field Gel Electrophoresis and PCR were utilized to assess strain typing and identify key resistance genes, revealing a strong link between prior carbapenem use and bacteremia development.
  • Among non-Metallo-β-Lactamase isolates, there was a notable prevalence of AmpC overproduction and alterations in OprD porin, indicating that intrinsic resistance mechanisms play a significant role in promoting multi-drug resistance.
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Pseudomonas aeruginosa is an opportunistic pathogen that causes frequently nosocomial infections, currently becoming more difficult to treat due to the various resistance mechanisms and different virulence factors. The purpose of this study was to determine the risk factors independently associated with the development of bacteremia by carbapenem-resistant P. aeruginosa, the frequency of virulence genes in metallo-β-lactamases producers and to evaluate their ability to produce biofilm.

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Article Synopsis
  • * Our case-control study revealed a high rate of MDR isolates (40.7%), with over half associated with inappropriate antibiotic therapy, resulting in significant complications for patients with bacteremia.
  • * Notably, we found mutations related to antibiotic resistance in almost all isolates, and we reported for the first time in Brazil the presence of specific resistance genes in isolates, emphasizing the urgent need for proper antibiotic treatment.
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This study evaluated the predictors of mortality and the impact of inappropriate therapy on the outcomes of patients with bacteraemia and ventilator-associated pneumonia (VAP). Additionally, we evaluated the correlation of the type III secretion system (TTSS) effector genotype with resistance to carbapenems and fluoroquinolones, mutations in the quinolone resistance-determining regions (QRDRs), metallo-β-lactamase and virulence factors. A retrospective cohort was conducted at a tertiary hospital in patients with multidrug-resistant (MDR) P.

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The rates of multidrug-resistant, extensively drug-resistant and pandrug-resistant isolates amongst non-fermenting Gram-negative bacilli, particularly Pseudomonas aeruginosa, have risen worldwide. The clinical consequence of resistance and the impact of adverse treatment on the outcome of patients with P. aeruginosa bacteraemia remain unclear.

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