Detection of mobile colistin resistance genes mcr-9.1 and mcr-10.1 in Enterobacter asburiae from Ecuadorian children.

Colistin is one of the last-line treatments for multi-drug resistant Gram-negative bacterial infections. The emergence of mobile colistin resistance genes has driven global concern and triggered the need for surveillance. Our report reveals the identification of mcr-9.1 and mcr-10.1 in Ecuador by employing a proximity ligation technique.

Raman spectra soft modeling of the biodiesel oxidation through evolving factor analysis & multivariate curve resolution.

The oxidative stability of biodiesel is defined by its relative resistance to the action of oxygen at room temperature. Its determination is an essential reference to the quality of biofuel and a significant parameter to be determined. This parameter concerns the quality of the biodiesel to be supplied to the consumer, and its determination is fundamental to maintaining the engine's proper functioning. Raman spectroscopy allows the rapid obtaining of structural information regarding biodiesel quality and, when aided by multivariate analysis methods, allows a quantitative determination of specific properties. This work uses Raman spectroscopy, Multivariate Curve Resolution with Alternative Least Squares (MCR-ALS) method, and Evolving Factor Analysis (EFA) to study biodiesel's oxidation kinetics. Also, the vibrational modes C = C, CH2, and CH3 were identified as the main structural groups involved in this process, corroborating previous studies. The MCR-ALS & EFA combination allowed modeling of the degradation kinetics following an A â†’ B â†’ C mechanism, where A corresponds to the biodiesel (starting material), B is related to the hydroperoxide mixture, and C is the final product. The results also suggested that this process follows a first-order reaction, with kinetic constant values of k1 = 0.0056 min-1 and k2 = 0.0031 min-1.

Multivariate curve resolution-based data fusion approaches applied in 1H NMR metabolomic analysis of healthy cohorts.

BACKGROUND: Metabolomics plays a critical role in deciphering metabolic alterations within individuals, demanding the use of sophisticated analytical methodologies to navigate its intricate complexity. While many studies focus on single biofluid types, simultaneous analysis of multiple matrices enhances understanding of complex biological mechanisms. Consequently, the development of data fusion methods enabling multiblock analysis becomes essential for comprehensive insights into metabolic dynamics. RESULTS: This study introduces a novel guideline for jointly analyzing diverse metabolomic datasets (serum, urine, metadata) with a focus on metabolic differences between groups within a healthy cohort. The guideline presents two fusion strategies, 'Low-Level data fusion' (LLDF) and 'Mid-Level data fusion' (MLDF), employing a sequential application of Multivariate Curve Resolution with Alternating Least Squares (MCR-ALS), linking the outcomes of successive analyses. MCR-ALS is a versatile method for analyzing mixed data, adaptable at various stages of data processing-encompassing resonance integration, data compression, and exploratory analysis. The LLDF and MLDF strategies were applied to 1H NMR spectral data extracted from urine and serum samples, coupled with biochemical metadata sourced from 145 healthy volunteers. SIGNIFICANCE: Both methodologies effectively integrated and analysed multiblock datasets, unveiling the inherent data structure and variables associated with discernible factors among healthy cohorts. While both approaches successfully detected sex-related differences, the MLDF strategy uniquely revealed components linked to age. By applying this analysis, we aim to enhance the interpretation of intricate biological mechanisms and uncover variations that may not be easily discernible through individual data analysis.

Environmental microbial colistin resistance in an elderly south Brazilian long-term care facility.

Colistin resistance is a global health concern, with antibiotics being the last treatment for Gram-negative bacteria infections. We aimed to identify colistin-resistant enterobacteria on environmental surfaces of a long-term care facility (LTCF) for the elderly in southern Brazil. Samples were collected and screened on MacConkey agar plus colistin, followed by API20E identification and PCR. Two isolates were founded and identified as Klebsiella pneumoniae and Providencia stuartii harboring mcr-1 gene with MICs > 128 µg mL-1 for colistin. This is the first isolation of microorganisms resistant to colistin in the environment of a LTCF for the elderly in south Brazil, urging monitoring programs to reduce environmental contamination by multiresistant microorganisms.

Prevalence of colistin-resistant Escherichia coli in foods and food-producing animals through the food chain: A worldwide systematic review and meta-analysis.

The purpose of this systematic review and meta-analysis was to summarize the available scientific evidence on the prevalence of colistin-resistant Escherichia coli strains isolated from foods and food-producing animals, the mobile colistin-resistant genes involved, and the impact of the associated variables. A systematic review was carried out in databases according to selection criteria and search strategies established a priori. Random-effect meta-analysis models were fitted to estimate the prevalence of colistin-resistant Escherichia coli and to identify the factors associated with the outcome. In general, 4.79% (95% CI: 3.98%-5.76%) of the food and food-producing animal samples harbored colistin-resistant Escherichia coli (total number of colistin-resistant Escherichia coli/total number of samples), while 5.70% (95% confidence interval: 4.97%-6.52%) of the E. coli strains isolated from food and food-producing animal samples harbored colistin resistance (total number of colistin-resistant Escherichia coli/total number of Escherichia coli isolated samples). The prevalence of colistin-resistant Escherichia coli increased over time (P < 0.001). On the other hand, 65.30% (95% confidence interval: 57.77%-72.14%) of colistin resistance was mediated by the mobile colistin resistance-1 gene. The mobile colistin resistance-1 gene prevalence did not show increases over time (P = 0.640). According to the findings, other allelic variants (mobile colistin resistance 2-10 genes) seem to have less impact on prevalence. A higher prevalence of colistin resistance was estimated in developing countries (P < 0.001), especially in samples (feces and intestinal content, meat, and viscera) derived from poultry and pigs (P < 0.001). The mobile colistin resistance-1 gene showed a global distribution with a high prevalence in most of the regions analyzed (>50%). The prevalence of colistin-resistant Escherichia coli and the mobile colistin resistance-1 gene has a strong impact on the entire food chain. The high prevalence estimated in the retail market represents a potential risk for consumers' health. There is an urgent need to implement based-evidence risk management measures under the "One Health" approach to guarantee public health, food safety, and a sustainable future.

Biodegradation of Polystyrene by Galleria mellonella: Identification of Potential Enzymes Involved in the Degradative Pathway.

Galleria mellonella is a lepidopteran whose larval stage has shown the ability to degrade polystyrene (PS), one of the most recalcitrant plastics to biodegradation. In the present study, we fed G. mellonella larvae with PS for 54 days and determined candidate enzymes for its degradation. We first confirmed the biodegradation of PS by Fourier transform infrared spectroscopy- Attenuated total reflectance (FTIR-ATR) and then identified candidate enzymes in the larval gut by proteomic analysis using liquid chromatography with tandem mass spectrometry (LC-MS/MS). Two of these proteins have structural similarities to the styrene-degrading enzymes described so far. In addition, potential hydrolases, isomerases, dehydrogenases, and oxidases were identified that show little similarity to the bacterial enzymes that degrade styrene. However, their response to a diet based solely on polystyrene makes them interesting candidates as a potential new group of polystyrene-metabolizing enzymes in eukaryotes.

Genomic characterization of New Delhi metallo-beta-lactamase-producing species of Morganellaceae, Yersiniaceae, and Enterobacteriaceae (other than Klebsiella) from Brazil over 2013-2022.

Over the last decade, New Delhi metallo-beta-lactamase (NDM) carbapenemase has silently spread in Brazil. In this study, we analyzed a large collection of Enterobacterales other than Klebsiella spp. received in our reference laboratory between 2013 and 2022. A total of 32 clinical isolates displaying different pulsed-field gel electrophoresis profiles, and represented by 11 species in the families Enterobacteriaceae (Citrobacter freundii, Citrobacter portucalensis, Enterobacter hormaechei, and Escherichia coli), Morganellaceae (Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, and Raoultella ornithinolytica), and Yersiniaceae (Serratia marcescens) had their whole genomes sequenced and further analyzed. Antimicrobial susceptibility was determined by disk diffusion, except for polymyxin B, assessed by broth microdilution. The blaNDM-1 allele was predominant (n = 29), but blaNDM-5 was identified in an E. coli specimen with a novel ST, and the blaNDM-7 allele was found in E. hormaechei ST45 and E. coli ST1049. Polymyxin was active against all but one Enterobacteriaceae isolate: an mcr-1-producing E. coli presenting minimal inhibitory concentration (4 mg/L). Isolates producing extended-spectrum ß-lactamases were common: cefotaximase from Munich (CTX-M)-15 (n = 10), CTX-M-2 (n = 4), and CTX-M-8 (n = 3) were detected, and the mcr-1-producing E. coli was found to co-produce both CTX-M-8 and CTX-M-55 ß-lactamases. The mcr-9 gene was found in 5/8 E. hormaechei isolates, distributed in four different sequence types, all of them presenting susceptibility to polymyxin. This study showed that NDM-producing Enterobacterales other than Klebsiella are already spread in Brazil, in diversified species, and cocarrying important resistance genes. Prompt detection and effective implementation of measures to prevent further spread are mandatory for mitigating the dissemination of NDM carbapenemase in hospital settings and preserving the already limited antimicrobial therapy options.

Traditional marketed meats as a reservoir of multidrug-resistant Escherichia coli.

This study aimed to analyze Escherichia coli from marketed meat samples in Peru. Sixty-six E. coli isolates were recovered from 21 meat samples (14 chicken, 7 beef), and antimicrobial resistance levels and the presence of mechanisms of antibiotic resistance, as well as clonal relationships and phylogeny of colistin-resistant isolates, were established. High levels of antimicrobial resistance were detected, with 93.9% of isolates being multi-drug resistant (MDR) and 76.2% of samples possessing colistin-resistant E. coli; of these, 6 samples from 6 chicken samples presenting mcr-1-producer E. coli. Colistin-resistant isolates were classified into 22 clonal groups, while phylogroup A (15 isolates) was the most common. Extended-spectrum ß-lactamase- and pAmpC-producing E. coli were found in 18 and 8 samples respectively, with blaCTX-M-55 (28 isolates; 16 samples) and blaCIT (8 isolates; 7 samples) being the most common of each type. Additionally, blaCTX-M-15, blaCTX-M-65, blaSHV-27, blaOXA-5/10-like, blaDHA, blaEBC and narrow-spectrum blaTEM were detected. In addition, 5 blaCTX-M remained unidentified, and no sought ESBL-encoding gene was detected in other 6 ESBL-producer isolates. The tetA, tetE and tetX genes were found in tigecycline-resistant isolates. This study highlights the presence of MDR E. coli in Peruvian food-chain. The high relevance of CTX-M-55, the dissemination through the food-chain of pAmpC, as well as the high frequency of unrelated colistin-resistant isolates is reported.

Detection of Plasmid-Mediated Resistance against Colistin in Multi-Drug-Resistant Gram-Negative Bacilli Isolated from a Tertiary Hospital.

The aim of this study was to determine the prevalence of plasmid-mediated colistin resistance mcr-1 to mcr-5 genes among colistin and multi-drug-resistant Gram-negative bacilli strains isolated from patients in a tertiary hospital in Toluca, Mexico. The presence of mcr genes among the 241 strains collected was assessed by PCR. In the case of mcr-carrying E. coli, further PCR tests were performed to determine the presence of blaCTX-M and whether the strains belonged to the O25b-ST131 clone. Conjugation experiments were also carried out to assess the horizontal transmission of colistin resistance. A total of twelve strains (5.0%), of which four were E. coli; four were P. aeruginosa; three were K. pneumoniae, and one E. cloacae, were found to be resistant to colistin. Of these strains, two E. coli isolates were found to carry mcr-1, and Southern blot hybridization demonstrated its presence on an approximately 60 kb plasmid. Both mcr-1-carrying E. coli strains were found to co-express blaCTX-M, belong to the O25b-ST131 clone, and horizontally transmit their colistin resistance. The results of this study confirm the presence of plasmid-mediated colistin resistance in hospitalized patients in Mexico and demonstrated that the multi-drug-resistant O25b-ST131 E. coli clone can acquire mcr genes and transmit such resistance traits to other bacteria.

Raman mapping for determination of TiO2 in different solid food samples by multivariate curve resolution with alternating least squares.

Titanium dioxide is a food additive commonly used as a white food coloring (E171). Its wide use by the food industry associated with the nanometric size distribution of the particles of this pigment has shown high genotoxicity associated with recurrent exposure by ingestion. Therefore, the use of E171 in food products has already been banned by some industries and in the European Union. Such banishment should soon be extended to other countries around the world, making it important to establish techniques for the efficient determination of TiO2 in different food products. The association between hyperspectral images and chemometric tools can be useful in this sense, aiming to enable the use of a single method for sample preparation and analysis of different types of food. Thus, the present work aims to evaluate the use of Raman mapping associated with the resolution of multivariate curves with alternating least squares (MCR-ALS) for the determination of titanium dioxide in solid food samples with different compositions, without the need to introduce specific sample preparation. The proposed method allowed for the first-time quantification of TiO2 in different food matrices without specific sample preparation, with a simple, rapid, accurate (93% of recovery), low detection limits (0.0111% m/m) and quantification (0.0370% m/m) and adequate linearity (r = 0.9990) and precise (standard deviation around 0.020-0.030% w/w) methodology. Such results highlight the potential use of Raman mapping associated with the MCR-ALS for quantification of the nano-TiO2 in commercial samples.

Genomic analysis of multidrug-resistant Escherichia coli strains carrying the mcr-1 gene recovered from pigs in Lima-Peru.

Antibiotic resistance is a current problem that significantly impacts overall health. The dissemination of antibiotic resistance genes (ARGs) to urban areas primarily occurs through ARG-carrying bacteria present in the gut microbiota of animals raised in intensive farming settings, such as pig production. Hence, this study aimed to isolate and analyzed 87 Escherichia coli strains from pig fecal samples obtained from intensive farms in Lima Department. The isolates were subjected to Kirby-Bauer-Disk Diffusion Test and PCR for mcr-1 gene identification. Disk-diffusion assay revealed a high level of resistance among these isolates to oxytetracycline, ampicillin, cephalothin, chloramphenicol, ciprofloxacin, and doxycycline. PCR analysis identified the mcr-1 gene in 8% (7/87) E. coli isolates. Further, whole genome sequencing was conducted on 17 isolates, including multidrug resistance (MDR) E. coli and/or mcr-1 gene carriers. This analysis unveiled a diverse array of ARGs. Alongside the mcr-1 gene, the blaCTX-M55 gene was particularly noteworthy as it confers resistance to third generation cephalosporins, including ceftriaxone. MDR E. coli genomes exhibited other ARGs encoding resistance to fosfomycin (fosA3), quinolones (qnrB19, qnrS1, qnrE1), tetracyclines (tetA, tetB, tetD, tetM), sulfonamides (sul1, sul2, sul3), amphenicols (cmlA1, floR), lincosamides (inuE), as well as various aminoglycoside resistance genes. Additionally, Multi Locus Sequence Typing (MLST) revealed a high diversity of E. coli strains, including ST10, a pandemic clone. This information provides evidence of the dissemination of highly significant ARGs in public health. Therefore, it is imperative to implement measures aimed at mitigating and preventing the transmission of MDR bacteria carrying ARGs to urban environments.

Co-Harboring of Beta-Lactamases and mcr-1 Genes in Escherichia coli and Klebsiella pneumoniae from Healthy Carriers and Backyard Animals in Rural Communities in Ecuador.

Few studies have addressed drug resistance of Enterobacterales in rural communities in developing countries. This study aimed to determine the coexistence of extended-spectrum ß-lactamase (ESBL) and carbapenemase genes in Escherichia coli and Klebsiella pneumoniae strains carrying the mcr-1 gene in rural communities in Ecuador from healthy humans and their backyard animals. Sixty-two strains, thirty E. coli and thirty-two K. pneumoniae strains carrying the mcr-1 gene were selected from a previous study. PCR were performed for the presence of ESBLs and carbapenemase genes. The strains were further characterized, and the genetic relationship was studied with multi-locus sequencing typing (MLST) of seven housekeeping genes. Fifty-nine of the sixty-two mcr-1 isolates (95%) harbored at least on ß-lactam resistance gene. The most prevalent ESBL genes were the blaTEM genes (present in in 80% of the E. coli strains) and the blaSHV gene (present in 84% of the K. pneumoniae strains). MSLT analysis revealed 28 different sequence types (ST); 15 for E. coli and 12 for K. pneumoniae, with most ST never described in humans and animals. The coexistence of mcr-1 and ß-lactams resistant genes in E. coli and K. pneumoniae strains is alarming and threatens the efficacy of last-resort antibiotics. Our findings highlight backyard animals as a reservoir of mcr-1/ß-lactams resistant genes.

Molecular typing of mcr-1 Escherichia coli isolates from pigs and farm environment based on fumC and fimH alleles.

Background: The dissemination of polymyxin resistance represents a significant threat to public health. Materials & methods: Sequence-based typing was performed by 53 mcr-1 Escherichia coli isolates using fumC/fimH (CH) genes to characterize clones spreading from pig farming. Furthermore, 12 isolates had their whole genome sequenced for phylogenetic study. Results: The isolates were classified into 22 distinct CH types, and two novel CH types (CH41-1578 and CH4-1579) and one sequence type (ST12652) was also described. According to phylogenetic study, both multilocus sequence typing and CH methods grouped the isolates similarly. Conclusion: Our findings suggest that the dissemination of the mcr-1 gene in pig farming has occurred mainly by horizontal gene transfer, and CH typing proved to be a good tool to characterize E. coli clones.

Genomic analysis of Klebsiella pneumoniae high-risk clone ST11 co-harbouring MCR-1.27 and KPC-2 recovered at a paediatric oncologic hospital in the Brazilian Amazon region.

OBJECTIVES: The horizontal transfer of antibiotic resistance genes in Gram-negative bacteria, mainly through plasmids, is one of the greatest concerns for health systems worldwide and has been a growing threat in hospitals related to healthcare-associated infections by multidrug-resistant bacteria. Here we present p henotypic and genomic characterization of a KPC-2 and MCR-1.27-producing Klebsiella pneumoniae strain isolated from a paediatric patient at an oncologic hospital in Belém, Pará State, Brazilian Amazon region. METHODS: Antibiotic susceptibility test, whole genome sequencing, and in silico analysis were used to characterize the bacterial isolate (IEC48020) received in the Evandro Chagas Institute. RESULTS: The isolate was resistant to carbapenems, colistin, polymyxin B, and several other antimicrobials and was susceptible in vitro just to tigecycline, classified as an extensively drug-resistant phenotype. Genomic analysis revealed IEC48020 strain belonged to sequence type 11, clonal complex 258 high-risk clone and the presence of eight plasmids, two of them harbouring mcr-1.27 and blaKPC-2 genes, and the presence of virulence-related genes encoding yersiniabactin, phospholipase D, and traT genes. CONCLUSIONS: The presence and dissemination of high-risk clone bacteria with high disseminating plasmids containing antibiotic resistance genes for last resource antibiotics treatment options is a threat to the healthcare system and demands efforts in surveillance and epidemiological research for better knowledge of the actual situation of antibiotic resistance in the healthcare system, especially in the Amazon region, Brazil.

Identification of mcr-1 Genes and Characterization of Resistance Mechanisms to Colistin in Escherichia coli Isolates from Colombian Hospitals.

We report the presence of the mcr-1 gene among 880 Escherichia coli clinical isolates collected in 13 hospitals from 12 Colombian cities between 2016 and 2019. Seven (0.8%) isolates were colistin resistant (MIC ≥ 4 µg/mL). These colistin-resistant isolates were screened for the presence of the mcr-1 gene; five carried the gene. These five isolates were subjected to whole genome sequencing (WGS) to identify additional resistomes and their ST. In addition, antimicrobial susceptibility testing revealed that all E. coli isolates carrying mcr-1 were susceptible to third generation-cephalosporin and carbapenems, except one, which carried an extended-spectrum ß-lactamase (CTX-M-55), along with the fosfomycin resistance encoding gene, fosA. WGS indicated that these isolates belonged to four distinct sequence types (ST58, ST46, ST393, and a newly described ST14315) and to phylogroups B1, A, and D. In this geographic region, the spread of mcr-1 in E. coli is low and has not been inserted into high-risk clones such as ST131, which has been present in the country longer.

First Known Report of mcr-Harboring Enterobacteriaceae in the Dominican Republic.

Colistin is a last-resort antibiotic used to treat infections caused by multidrug-resistant Gram-negative bacteria. People with a history of travel to the Dominican Republic have become sick with pathogenic bacteria carrying the mobile colistin resistance gene, mcr-1, during and after traveling. This investigation aimed to identify mcr genes in Enterobacteriaceae isolated from food animal sources in the Dominican Republic. Three hundred and eleven samples were tested, from which 1354 bacterial isolates were obtained. Real-time PCR tests showed that 70.7% (220 out of 311) of the samples and 3.2% (44 out of 1354) of the isolates tested positive for the mcr gene. All RT-PCR presumptive mcr-positive isolates (n = 44) and a subset (n = 133) of RT-PCR presumptive mcr-negative isolates were subjected to whole-genome sequencing. WGS analysis showed that 39 isolates carried the mcr gene, with 37 confirmed as positive through RT-PCR and two as negative. Further, all of the mcr-positive genomes were identified as Escherichia coli and all contained a IncX4 plasmid replicon. Resistant determinants for other antibiotics important for human health were found in almost all isolates carrying mcr genes.

Ligand binding free energy evaluation by Monte Carlo Recursion.

The correct evaluation of ligand binding free energies by computational methods is still a very challenging active area of research. The most employed methods for these calculations can be roughly classified into four groups: (i) the fastest and less accurate methods, such as molecular docking, designed to sample a large number of molecules and rapidly rank them according to the potential binding energy; (ii) the second class of methods use a thermodynamic ensemble, typically generated by molecular dynamics, to analyze the endpoints of the thermodynamic cycle for binding and extract differences, in the so-called 'end-point' methods; (iii) the third class of methods is based on the Zwanzig relationship and computes the free energy difference after a chemical change of the system (alchemical methods); and (iv) methods based on biased simulations, such as metadynamics, for example. These methods require increased computational power and as expected, result in increased accuracy for the determination of the strength of binding. Here, we describe an intermediate approach, based on the Monte Carlo Recursion (MCR) method first developed by Harold Scheraga. In this method, the system is sampled at increasing effective temperatures, and the free energy of the system is assessed from a series of terms W(b,T), computed from Monte Carlo (MC) averages at each iteration. We show the application of the MCR for ligand binding with datasets of guest-hosts systems (N = 75) and we observed that a good correlation is obtained between experimental data and the binding energies computed with MCR. We also compared the experimental data with an end-point calculation from equilibrium Monte Carlo calculations that allowed us to conclude that the lower-energy (lower-temperature) terms in the calculation are the most relevant to the estimation of the binding energies, resulting in similar correlations between MCR and MC data and the experimental values. On the other hand, the MCR method provides a reasonable view of the binding energy funnel, with possible connections with the ligand binding kinetics, as well. The codes developed for this analysis are publicly available on GitHub as a part of the LiBELa/MCLiBELa project (https://github.com/alessandronascimento/LiBELa).

Genomic characterization of new Delhi metallo-beta-lactamase-producing species of Morganellaceae, Yersiniaceae, and Enterobacteriaceae (other than Klebsiella) from Brazil over 2013-2022

Over the last decade, New Delhi metallo-beta-lactamase (NDM) carbapenemase has silently spread in Brazil. In this study, we analyzed a large collection of Enterobacterales other than Klebsiella spp. received in our reference laboratory between 2013 and 2022. A total of 32 clinical isolates displaying different pulsed-field gel electrophoresis profiles, and represented by 11 species in the families Enterobacteriaceae (Citrobacter freundii, Citrobacter portucalensis, Enterobacter hormaechei, and Escherichia coli), Morganellaceae (Morganella morganii, Proteus mirabilis, Proteus vulgaris, Providencia rettgeri, Providencia stuartii, and Raoultella ornithinolytica), and Yersiniaceae (Serratia marcescens) had their whole genomes sequenced and further analyzed. Antimicrobial susceptibility was determined by disk diffusion, except for polymyxin B, assessed by broth microdilution. The blaNDM-1 allele was predominant (n = 29), but blaNDM-5 was identified in an E. coli specimen with a novel ST, and the blaNDM-7 allele was found in E. hormaechei ST45 and E. coli ST1049. Polymyxin was active against all but one Enterobacteriaceae isolate: an mcr-1–producing E. coli presenting minimal inhibitory concentration (4 mg/L). Isolates producing extended-spectrum β-lactamases were common: cefotaximase from Munich (CTX-M)-15 (n = 10), CTX-M-2 (n = 4), and CTX-M-8 (n = 3) were detected, and the mcr-1–producing E. coli was found to co-produce both CTX-M-8 and CTX-M-55 β-lactamases. The mcr-9 gene was found in 5/8 E. hormaechei isolates, distributed in four different sequence types, all of them presenting susceptibility to polymyxin. This study showed that NDM-producing Enterobacterales other than Klebsiella are already spread in Brazil, in diversified species, and cocarrying important resistance genes. Prompt detection and effective implementation of measures to prevent further spread are mandatory for mitigating the dissemination of NDM carbapenemase in hospital settings and preserving the already limited antimicrobial therapy options.

Occurrence and Genomic Characterization of mcr-1-Harboring Escherichia coli Isolates from Chicken and Pig Farms in Lima, Peru.

Resistance to colistin generated by the mcr-1 gene in Enterobacteriaceae is of great concern due to its efficient worldwide spread. Despite the fact that the Lima region has a third of the Peruvian population and more than half of the national pig and poultry production, there are no reports of the occurrence of the mcr-1 gene in Escherichia coli isolated from livestock. In the present work, we studied the occurrence of E. coli carrying the mcr-1 gene in chicken and pig farms in Lima between 2019 and 2020 and described the genomic context of the mcr-1 gene. We collected fecal samples from 15 farms in 4 provinces of Lima including the capital Lima Metropolitana and recovered 341 E. coli isolates. We found that 21.3% (42/197) and 12.5% (18/144) of the chicken and pig strains were mcr-1-positive by PCR, respectively. The whole genome sequencing of 14 mcr-1-positive isolates revealed diverse sequence types (e.g., ST48 and ST602) and the presence of other 38 genes that confer resistance to 10 different classes of antibiotics, including beta-lactamase blaCTX-M-55. The mcr-1 gene was located on diverse plasmids belonging to the IncI2 and IncHI1A:IncHI1B replicon types. A comparative analysis of the plasmids showed that they contained the mcr-1 gene within varied structures (mikB-mcr1-pap2, ISApl1-mcr1-pap2, and Tn6330). To the best of our knowledge, this is the first attempt to study the prevalence of the mcr-1 gene in livestock in Peru, revealing its high occurrence in pig and chicken farms. The genetic diversity of mcr-1-positive strains suggests a complex local epidemiology calling for a coordinated surveillance under the One-Health approach that includes animals, retail meat, farmers, hospitals and the environment to effectively detect and limit the spread of colistin-resistant bacteria.

Multivariate strategy for identifying and quantifying jet fuel contaminants by MCR-ALS/PLS models coupled to combined MIR/NIR spectra.

The investigation and control of jet fuel contamination for private aircrafts has gained attention due to the softer monitoring in comparison to commercial aviation. The possible contamination with kerosene solvent (KS) makes this investigation more challenging, since it has physicochemical similarities with jet fuel. To help solve this problem, a chemometric methodology was applied in this research combining multivariate curve resolution with alternating least squares (MCR-ALS) and partial least squares (PLS) models coupled to near- and mid-infrared spectroscopies (MIR/NIR) in order to detect and quantify KS in blends with JET-A1 using 23 samples (5-60% v/v). Additionally, 98 samples were stored for 60 days, and principal component analysis, genetic algorithm, and successive projections algorithm were coupled to linear discriminant analysis (PCA-LDA, GA-LDA, and SPA-LDA) in order to classify the blends according to the bands assigned to oxidation products, such as phenols and carboxylic acids. GA-LDA and SPA-LDA models were accurate and reached 100% sensitivity and specificity. Physicochemical analysis was not able to detect the presence of KS in contaminated jet fuel samples, even in high concentrations. The use of MIR-NIR combined spectra improved the quantification results, thus decreasing the experimental error from 5.22% (using only NIR) to 1.64%. PLS regression quantified the content of KS with high accuracy (RMSEP < 1.64%, R2 > 0.995). The MCR-ALS model stood out for recovering the spectral profile of kerosene solvent by segregating it from jet fuel spectra. The development of models using chemometric tools contributed to a fast, low-cost, and efficient process for quality control that can be applied in the fuel industry.