Novel Megaplasmid Driving NDM-1-Mediated Carbapenem Resistance in ST1588 in South America.

Carbapenem-resistant Enterobacterales (CRE) is a critical public health problem in South America, where the prevalence of NDM metallo-betalactamases has increased substantially in recent years. In this study, we used whole genome sequencing to characterize a multidrug-resistant (MDR) (UCO-361 strain) clinical isolate from a teaching hospital in Chile. Using long-read (Nanopore) and short-read (Illumina) sequence data, we identified a novel un-typeable megaplasmid (314,976 kb, pNDM-1_UCO-361) carrying the carbapenem resistance gene within a Tn transposon.

Diversity and Host Relationships of the Mycoparasite (Hypocreales, Ascomycota) in Temperate Central Chile.

We present the first major survey of regional diversity, distribution and host-association of . Whereas the rather scarce worldwide records of this mycoparasitic fungus suggested no specific distribution pattern of most species before, we provide new evidence of endemic and specific host-parasite guilds of in Southern South America, including the description of a new species. The corresponding inventory was performed in temperate central Chile.

Molecular characterization and antibacterial activity of oral antibiotics and copper nanoparticles against endodontic pathogens commonly related to health care-associated infections.

Objective: To carry out molecular characterization and determine the antibacterial activity of oral antibiotics and copper nanoparticles (Cu-NPs) against endodontic strains isolated from persistent infections.

Materials And Methods: Root canal samples from 24 teeth in different patients with persistent endodontic infections were obtained. The isolated strains were identified by biochemical tests and 16S rDNA sequencing.

[Carbapenemases produced by Carbapenem-resistant Pseudomonas aeruginosa isolated from hospitals in Chile].

Background: Carbapenem resistance mediated by carbapenemases in Pseudomonas aeruginosa is an important mechanism; however, loss of porin OprD remains as the most frequent.

Aim: To determine the proportion of P. aeruginosa isolates, resistant to imipenem and/or meropenem, producing carbapenemases, the type of enzyme produced and the genetic relationship between the isolates.

Colistin Heteroresistance among Extended Spectrum β-lactamases-Producing .

Colistin-heteroresistant (CST-HR) Enterobacterales isolates have been identified recently, challenging the clinical laboratories since routine susceptibility tests fail to detect this phenotype. In this work we describe the first CST-HR phenotype in extended-spectrum β-lactamase (ESBL)-producing isolates in South America. Additionally, we determine the genomic mechanisms of colistin heteroresistance in these strains.

Antibiotic resistance in bacterial isolates from freshwater samples in Fildes Peninsula, King George Island, Antarctica.

Anthropic activity in Antarctica has been increasing considerably in recent years, which could have an important impact on the local microbiota affecting multiple features, including the bacterial resistome. As such, our study focused on determining the antibiotic-resistance patterns and antibiotic-resistance genes of bacteria recovered from freshwater samples collected in areas of Antarctica under different degrees of human influence. Aerobic heterotrophic bacteria were subjected to antibiotic susceptibility testing and PCR.

Role of wastewater treatment plants on environmental abundance of Antimicrobial Resistance Genes in Chilean rivers.

Background: Point sources such as wastewater treatment plants (WWTPs) commonly discharge their effluent into rivers. Their waste may include antibiotic residues, disinfectants, antibiotic resistant bacteria (ARB), and Antimicrobial Resistance Genes (ARG). There is evidence that ARG can be found in the natural environment, but attribution to specific point sources is lacking.

Evolutionary dynamics of carbapenem-resistant Acinetobacter baumannii circulating in Chilean hospitals.

We analyze the evolutionary dynamics of ninety carbapenem-resistant Acinetobacter baumannii (CRAB) isolates collected between 1990 and 2015 in Chile. CRAB were identified at first in an isolate collected in 2005, which harbored the ISAba1-bla arrangement. Later, OXA-58- and OXA-23-producing A.

Introduction of NDM-1 and OXA-370 from Brazil into Chile in strains of Klebsiella pneumoniae isolated from a single patient.

Carbapenemase-producing Enterobacteriaceae have rapidly disseminated worldwide and can colonize patients in healthcare centers. As in Chile the first isolations of NDM-1 and OXA-370 carbapenemases were related with a patient arriving from Brazil, the genetic relatedness of Klebsiella pneumoniae strains producers of these enzymes and isolated in both countries was assessed. PFGE analyses revealed that the isolates were clonally related, illustrating how travel contributes to the spread of multidrug-resistant microorganisms.

Genetic Platforms of in Carbapenemase-Producing Strains of Isolated in Chile.

To elucidate whether the genetic platforms of contribute to the phenotypes of multi-drug-resistance (MDR) in the first carbapenemase-producing strains isolated in Chile. Twenty-two carbapenemase-producing strains isolated from different Chilean patients and hospitals were studied. Their genetic relatedness was assessed by PFGE and MLST.

The efflux pump inhibitor phenylalanine-arginine β-naphthylamide (PAβN) increases resistance to carbapenems in Chilean clinical isolates of KPC-producing Klebsiella pneumoniae.

Objectives: KPC-producing strains present a wide range of carbapenem minimum inhibitory concentrations (MICs). This variation may be due to differential expression of bla and porin genes, efflux pump activity and the production of extended-spectrum β-lactamases and/or AmpC β-lactamases. The aim of this study was to determine the role of efflux pumps inhibited by phenylalanine-arginine β-naphthylamide (PAβN) in resistance to carbapenems in Chilean clinical isolates of bla-harbouring Klebsiella pneumoniae.

Diversity structure of culturable bacteria isolated from the Fildes Peninsula (King George Island, Antarctica): A phylogenetic analysis perspective.

It has been proposed that Antarctic environments select microorganisms with unique biochemical adaptations, based on the tenet 'Everything is everywhere, but, the environment selects' by Baas-Becking. However, this is a hypothesis that has not been extensively evaluated. This study evaluated the fundamental prediction contained in this hypothesis-in the sense that species are structured in the landscape according to their local habitats-, using as study model the phylogenetic diversity of the culturable bacteria of Fildes Peninsula (King George Island, Antarctica).

Molecular typing and genetic environment of the blaKPC gene in Chilean isolates of Klebsiella pneumoniae.

The aim of this work was to determine the genetic environment and transferability of blaKPC as well as the pulsotypes of KPC-producing Klebsiella pneumoniae strains isolated from clinical samples in Chilean hospitals. Seventeen strains, principally isolated in Santiago (the capital of Chile) during the years 2012 and 2013, were included. The genetic environment of blaKPC was elucidated by PCR mapping and sequencing.

The purified and recombinant Legionella pneumophila chaperonin alters mitochondrial trafficking and microfilament organization.

A portion of the total cellular pool of the Legionella pneumophila chaperonin, HtpB, is found on the bacterial cell surface, where it can mediate invasion of nonphagocytic cells. HtpB continues to be abundantly produced and released by internalized L. pneumophila and may thus have postinvasion functions.