Publications by authors named "Melano R"

Objective: The OXA-48-like enzymes have the capacity to hydrolyse carbapenems and are members of class D β-lactamases that are primarily detected in Enterobacterales. The allelic variant bla, which has low hydrolytic activity towards carbapenems, was detected in Argentina in 2011 and has spread successfully since then, giving sporadic origin to novel local variants. The aim of this study was to analyse the phenotypic profile and dissemination strategies of two novel OXA enzymes, bla and bla, located in Escherichia coli M17224 and Klebsiella pneumoniae M21014, respectively, isolated from two paediatric patients.

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Objective: Long COVID is a condition characterised by persistent symptoms after a SARS-CoV-2 infection, with neurological manifestations being particularly frequent. Existing research suggests that long COVID patients not only report cognitive symptoms but also exhibit measurable cognitive impairment. Neuroimaging studies have identified structural alterations in brain regions linked to cognitive functions.

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Background: Pseudomonas aeruginosa (PA) is a common cause of healthcare-associated infection (PA-HAI) in the intensive care unit (ICU).

Aim: To describe the epidemiology of PA-HAI in ICUs in Ontario, Canada, and to identify episodes of sink-to-patient PA transmission.

Methods: This was a prospective cohort study of patients in six ICUs from 2018 to 2019, with retrieval of PA clinical isolates, and PA-screening of antimicrobial-resistant organism surveillance rectal swabs, and of sink drain, air, and faucet samples.

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Mobile colistin resistance (mcr) genes were described recently in Gram-negative bacteria including carbapenem-resistant Enterobacterales. There are ten mcr genes described in different Gram-negative bacteria, however, Escherichia coli harboring mcr-1 gene is by far the most frequent combination. In Argentina, mcr-1 gene was characterized only on plasmids belonging to IncI2 group.

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The first cases of in Argentina were detected in three (Pre) recovered from two hospitals in Buenos Aires city in 2013. The isolates were genetically related, but the plasmid profile was different. Here, we characterized the -harboring plasmids of the first three cases detected in Argentina.

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We have investigated the prevalence of carbapenemase-producing uropathogens at the University Hospital of the West Indies, Jamaica. From 64 unique urine samples collected between January and March 2020, only 2 closely related Klebsiella pneumoniae (ST11, 14 SNPs of difference; no clear epidemiological links found between patients) were carbapenemase-producers. By whole-genome sequencing (WGS), was found on ~46 kb, IncX3 plasmid.

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Introduction: The aim of this study was to investigate the prevalence and distribution of AmpC beta-lactamases (BLs) in uropathogens ( and ) at the University Hospital of the West Indies Jamaica (UHWI).

Method: De-duplicated consecutive urine samples, collected from January to March 2020 at the UHWI, were analyzed. Screening and phenotypic confirmatory tests were conducted using resistance to cefoxitin and the Disc Approximation Test (DAT) respectively, for isolates of interest.

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During 2020-2021, countries in Latin America and the Caribbean reported clinical emergence of carbapenemase-producing Enterobacterales that had not been previously characterized locally, increased prevalence of carbapenemases that had previously been detected, and co-production of multiple carbapenemases in some isolates. These increases were likely fueled by changes related to the COVID-19 pandemic, including empirical antibiotic use for potential COVID-19-related bacterial infections and healthcare limitations resulting from the rapid rise in COVID-19 cases. Strengthening antimicrobial resistance surveillance, epidemiologic research, and infection prevention and control programs and antimicrobial stewardship in clinical settings can help prevent emergence and transmission of carbapenemase-producing Enterobacterales.

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A ceftazidime-avibactam-resistant KPC-producing Pseudomonas aeruginosa strain was isolated in Argentina from a tracheal aspirate. The patient was treated with ceftazidime-avibactam in combination with other agents for 130 days. Whole-genome sequencing of P.

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Background: Currently, in Latin America, including Peru, the treatment of gonorrhea is still empiric and information regarding antimicrobial resistance is scarce in some countries because of the limited resources, which can contribute to the rising rates of reported multidrug-resistant gonococcal strains. In that context, it is mandatory to continuously monitor and report antimicrobial resistance in N. gonorrhoeae to update treatment recommendations.

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Short-read sequencing can provide detection of multiple genomic determinants of antimicrobial resistance from single bacterial genomes and metagenomic samples. Despite its increasing application in human, animal, and environmental microbiology, including human clinical trials, the performance of short-read Illumina sequencing for antimicrobial resistance gene (ARG) detection, including resistance-conferring single nucleotide polymorphisms (SNPs), has not been systematically characterized. Using paired-end 2 × 150 bp (base pair) Illumina sequencing and an assembly-based method for ARG prediction, we determined sensitivity, positive predictive value (PPV), and sequencing depths required for ARG detection in an Escherichia coli isolate of sequence type (ST) 38 spiked into a synthetic microbial community at varying abundances.

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Shiga toxin-producing (STEC) is known as a pathogen associated with food-borne diseases. The STEC O145 serogroup has been related with acute watery diarrhea, bloody diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Argentina has the highest rate of HUS worldwide with 70% of the cases associated with STEC infections.

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The N501Y amino acid mutation caused by a single point substitution A23063T in the spike gene of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is possessed by three variants of concern (VOCs), B.1.1.

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Objectives: Performance characteristics of SARS-CoV-2 nucleic acid detection assays are understudied within contexts of low pre-test probability, including screening asymptomatic persons without epidemiological links to confirmed cases, or asymptomatic surveillance testing. SARS-CoV-2 detection without symptoms may represent presymptomatic or asymptomatic infection, resolved infection with persistent RNA shedding, or a false-positive test. This study assessed the positive predictive value of SARS-CoV-2 real-time reverse transcription polymerase chain reaction (rRT-PCR) assays by retesting positive specimens from 5 pre-test probability groups ranging from high to low with an alternate assay.

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Article Synopsis
  • A study in a hospital system in Ontario evaluated how whole-genome sequencing (WGS) could enhance understanding of carbapenemase-producing Enterobacteriaceae (CPE) transmission during a specific time frame from 2007 to 2018.
  • Researchers analyzed data from 85 CPE-infected or colonized patients, identifying seven epidemiological transmission clusters; WGS confirmed some clusters and revealed additional cases not previously linked by traditional methods.
  • The findings suggest WGS can effectively uncover hidden transmission routes and improve strategies for preventing and controlling CPE spread in healthcare settings.
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In 2018 to 2019, PCR for carbapenemases in routine Gram-negative isolates submitted to the National Microbiology Laboratory revealed an increase in IMP-type metalloenzyme-positive isolates, mostly among Whole-genome sequencing revealed that 23 harbored within a chromosomal Tn element. Phylogenomics indicated diversity of isolates but also the presence of a few clonal isolates dispersed geographically. These isolates may be difficult to detect due to carbapenem susceptibility and false-negative results in phenotypic testing.

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To investigate the mobile genetic elements harboring gene in carbapenem-resistant recovered during a 6-month outbreak in a high-complexity hospital from Ecuador. A total of 62 isolates belonging to ST258 -positive ( = 45), ST25 serotype K2 ( = 8), ST348 ( = 6), ST42 ( = 1), ST196 ( = 1), and ST1758 ( = 1) were collected from intensive care unit (ICU), neurosurgery, burn unit, internal medicine, pneumology, and neurology. Pulsed-field gel electrophoresis analysis showed two major clusters of ST258 and ST25 related to bloodstream infections and pneumonia circulating in ICU.

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Surveillance data from Southern Ontario show that a majority of Verona Integron-encoded Metallo-β-lactamase (VIM)-producing Enterobacteriaceae are locally acquired. To better understand the local epidemiology, we analysed clinical and environmental bla-positive Enterobacteriaceae from the area. Clinical samples were collected within the Toronto Invasive Bacterial Diseases Network (2010-2016); environmental water samples were collected in 2015.

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Objectives: Acinetobacter baumannii is an opportunistic nosocomial pathogen that is the main focus of attention in clinical settings owing to its intrinsic ability to persist in the hospital environment and its capacity to acquire determinants of resistance and virulence. Here we present the genomic sequencing, molecular characterisation and genomic comparison of two A. baumannii strains belonging to two different sequence types (STs), one sporadic and one widely distributed in our region.

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Background: Data on household transmission of carbapenemase-producing Enterobacterales (CPE) remain limited. We studied risk of CPE household co-colonization and transmission in Ontario, Canada.

Methods: We enrolled CPE index cases (identified via population-based surveillance from January 2015 to October 2018) and their household contacts.

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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.

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The rising rates of antibiotic resistance increasingly compromise empirical treatment. Knowing the antibiotic susceptibility of a pathogen's close genetic relative(s) may improve empirical antibiotic selection. Using genomic and phenotypic data for isolates from three separate clinically derived databases, we evaluated multiple genomic methods and statistical models for predicting antibiotic susceptibility, focusing on potentially rapidly available information, such as lineage or genetic distance from archived isolates.

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Objective: The aim of this study was to detect potential animal reservoirs of Escherichia coli carrying the mcr-1 gene in an Ecuadorian household.

Methods: The mobile colistin-resistance gene, mcr-1, was first detected in Ecuador in a commensal E. coli isolate from a boy.

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In Argentina, NDM metallo-β-lactamase was first reported in 2013. By now, it has disseminated throughout the country in diverse Gram negative bacteria. Here, we report the case of a paediatric patient that underwent a 1-year hospitalisation due to erythrodermic psoriasis in 2014 and received multiple antimicrobial treatments.

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