Fish are poor sentinels for surveillance of riverine antimicrobial resistance.

Effective surveillance of antimicrobial resistance (AMR) in the environment is crucial for assessing the human and animal health risk of AMR pollution. Wastewater treatment plants (WWTPs) are one of the main sources of AMR pollutants discharged into water bodies. One important factor for assessing the risks associated with such pollution is the colonization potential of the resistant bacteria (ARB) and resistance genes (ARGs) from the environment into human or animal microbiomes upon exposure.

Effects of Cigarette-Derived Compounds on the Spread of Antimicrobial Resistance in Artificial Human Lung Sputum Medium, Simulated Environmental Media, and Wastewater.

Background: Antimicrobial resistance (AMR) and smoking of tobacco products are two of the most important threats to global human health. Both are associated with millions of deaths every year. Surprisingly, the immediate interactions between these two threats remain poorly understood.

Jellyfish blooms-an overlooked hotspot and potential vector for the transmission of antimicrobial resistance in marine environments.

Gelatinous zooplankton (GZ) represents an important component of marine food webs, capable of generating massive blooms with severe environmental impact. When these blooms collapse, considerable amounts of organic matter (GZ-OM) either sink to the seafloor or can be introduced into the ocean's interior, promoting bacterial growth and providing a colonizable surface for microbial interactions. We hypothesized that GZ-OM is an overlooked marine hotspot for transmitting antimicrobial resistance genes (ARGs).

Environmental microbiome diversity and stability is a barrier to antimicrobial resistance gene accumulation.

When antimicrobial resistant bacteria (ARB) and genes (ARGs) reach novel habitats, they can become part of the habitat's microbiome in the long term if they are able to overcome the habitat's biotic resilience towards immigration. This process should become more difficult with increasing biodiversity, as exploitable niches in a given habitat are reduced for immigrants when more diverse competitors are present. Consequently, microbial diversity could provide a natural barrier towards antimicrobial resistance by reducing the persistence time of immigrating ARB and ARG.

Genomic characterization of bla-harbouring plasmids recovered from Pseudomonas aeruginosa.

Objectives: To the best of our knowledge, no genomic descriptions of bla-harbouring plasmids are available in literature so far. The aim of this study was to describe the genomic features of three bla-harbouring plasmids recovered from Pseudomonas aeruginosa isolated in Argentina in different periods.

Methods: bla-harbouring plasmids from three clinical P.

Trimethoprim resistance in surface and wastewater is mediated by contrasting variants of the dfrB gene.

Trimethoprim (TMP) is a low-cost, widely prescribed antibiotic. Its effectiveness is increasingly challenged by the spread of genes coding for TMP-resistant dihydrofolate reductases: dfrA, and the lesser-known, evolutionarily unrelated dfrB. Despite recent reports of novel variants conferring high level TMP resistance (dfrB10 to dfrB21), the prevalence of dfrB is still unknown due to underreporting, heterogeneity of the analyzed genetic material in terms of isolation sources, and limited bioinformatic processing.

Reduced selection for antibiotic resistance in community context is maintained despite pressure by additional antibiotics.

Selection for antibiotic resistance at very low antibiotic concentrations has been demonstrated for individual antibiotics in single species experiments. Furthermore, selection in these focal strains is reduced when taking place in complex microbial community context. However, in the environment, bacteria are rarely exposed to single, but rather complex mixtures of selective agents.

Quantification of the mobility potential of antibiotic resistance genes through multiplexed ddPCR linkage analysis.

There is a clear need for global monitoring initiatives to evaluate the risks of antibiotic resistance genes (ARGs) towards human health. Therefore, not only ARG abundances within a given environment, but also their potential mobility, hence their ability to spread to human pathogenic bacteria needs to be quantified. We developed a novel, sequencing-independent method for assessing the linkage of an ARG to a mobile genetic element by statistical analysis of multiplexed droplet digital PCR (ddPCR) carried out on environmental DNA sheared into defined, short fragments.

Emergence and clonal expansion of Klebsiella pneumoniae ST307, simultaneously producing KPC-3 and NDM-1.

MDR Klebsiella pneumoniae ST307 is a high-risk clone, whose genetic features contribute to its adaptation to hospital environments and the human host. This study describes the emergence and clonal dissemination of K. pneumoniae ST307, recovered during November 2018 to February 2019 in a hospital in Buenos Aires city, which concurrently harbored KPC-3 and NDM-1.

Characterisation of blaharbouring plasmids recovered from Pseudomonas aeruginosa ST654 and ST235 high-risk clones.

Objective: The main objectives were to describe two bla plasmids recovered from Pseudomonas aeruginosa isolates belonging to the ST654 and ST235 high-risk clones, and to compare with complete sequences of bla harbouring plasmids available in public databases.

Methods: Antimicrobial susceptibility was determined according to CLSI (Clinical and Laboratory Standards Institute) guidelines. Genomes were sequenced using an Illumina MiSeq platform, and bla plasmid sequences were achieved using MinION platform.

Full characterization of an IncR plasmid harboring qnrS1 recovered from a VIM-11-producing Pseudomonas aeruginosa.

Metallo-β-lactamases (MBL) producing Pseudomonas aeruginosa isolates have been well characterized. Quinolones are commonly used in the treatment of carbapenem-resistant P. aeruginosa infections; however, data about PMQR in this species are scarce.

Changing epidemiology of KPC-producing Klebsiella pneumoniae in Argentina: Emergence of hypermucoviscous ST25 and high-risk clone ST307.

Objectives: To assess the epidemiological features of 76 Klebsiella pneumoniae carbapenemase (KPC)-producing Klebsiella pneumoniae (KPC-Kp) isolates recovered from three hospitals in Buenos Aires, Argentina, during 2015-2017.

Methods: Antimicrobial susceptibilities were determined according to CLSI Clinical and Laboratoy Standards guidelines. Molecular typing of KPC-Kp was performed by pulsed-field gel electrophoresis (PFGE)-Xbal and multilocus sequence typing.

Co-occurrence of clinically relevant β-lactamases and MCR-1 encoding genes in Escherichia coli from companion animals in Argentina.

Extended-spectrum β-lactamase (ESBL), plasmid-mediated AmpC (pAmpC) and MCR-1 phosphoethanolamine transferase enzymes have been pointed out as the main plasmid-mediated mechanisms of resistance to third generation cephalosporins (TGC) and colistin, respectively, and are currently considered a major concern both in human and veterinary medicine. Little data on these resistance determinants prevalence in companion animal infections is available. The aim of this study was to determine the resistance profile of Escherichia coli isolated from pet infections, in Argentina, and to characterize the resistance mechanisms to TGC, as well as the presence of the plasmid-borne colistin resistance gene, mcr-1.

Spread of Clonally Related Escherichia coli Strains Harboring an IncA/C Plasmid Encoding IMP-8 and Its Recruitment into an Unrelated MCR-1-Containing Isolate.

Ten IMP-8-producing isolates were recovered from surveillance cultures of a neonatal intensive care unit; eight of the isolates were clonally related. A 168.2-kb plasmid was fully sequenced, and it corresponded to the recently described IncA/C1-ST13 plasmid.

First isolate of KPC-2-producing Klebsiella pneumonaie sequence type 23 from the Americas.

KPC-2-producing Klebsiella pneumoniae isolates mainly correspond to clonal complex 258 (CC258); however, we describe KPC-2-producing K. pneumoniae isolates belonging to invasive sequence type 23 (ST23). KPC-2 has scarcely been reported to occur in ST23, and this report describes the first isolation of this pathogen in the Americas.