Antimicrobial resistance and mortality following E. coli bacteremia

Exploring α, β-unsaturated carbonyl compounds against bacterial efflux pumps via computational approach

Antibiotic resistance has become a pressing global health crisis, with bacterial infections increasingly difficult to treat due to the emergence of multidrug resistance. This study aims to identify potential chalcone molecules that interact with two key multidrug efflux pumps, AcrB and EmrD, of Escherichia coli, using advanced computational tools. In silico ADMET (absorption, distribution, metabolism, excretion, and toxicity), drug-likeness prediction, molecular docking, and molecular dynamics simulation analyses were conducted on a ligand library comprising 100 chalcone compounds against AcrB (PDB: 4DX5) and EmrD (PDB: 2GFP). The results demonstrated that Elastichalcone A (PubChem CID 102103730) exhibited a remarkable binding affinity of -9.9 kcal/mol against AcrB, while 4'-methoxy-4-hydroxychalcone (PubChem CID 5927890) displayed a binding affinity of -9.8 kcal/mol against EmrD. Both ligands satisfied drug-likeness rules and possessed favorable pharmacokinetic profiles. Molecular dynamics simulation of the AcrB-Elastichalcone A complex remained stable over 100 ns, with minimal fluctuations in root-mean-square deviation and root-mean-square fluctuation. The screened ligand library demonstrated good drug-likeness and pharmacokinetic properties. Moreover, the MM/PB(GB)SA calculation indicated the tight binding and thermodynamic stability of the simulated protein-ligand complexes. Overall, this study highlights the potential of chalcones as promising candidates for targeting multidrug efflux pumps, offering a potential strategy to overcome antibiotic resistance. Further exploration and optimization of these compounds may lead to the development of effective therapeutics against multidrug-resistant bacterial infections.Communicated by Ramaswamy H. Sarma.

Impact of ESKAPE Pathogens on Bacteremia: A Three-Year Surveillance Study at a Major Hospital in Southern Italy

BACKGROUND/OBJECTIVES

ESKAPE pathogens (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.) pose a serious public health threat as they are resistant to multiple antimicrobial agents. Bloodstream infections (BSIs) caused by ESKAPE bacteria have high mortality rates due to the limited availability of effective antimicrobials. This study aimed to evaluate the prevalence and susceptibility of ESKAPE pathogens causing BSIs over three years in a large tertiary hospital in Salerno.

METHODS

Conducted at the Clinical Microbiology Laboratory of San Giovanni di Dio e ''Ruggi D'Aragona'' Hospital from January 2020 to December 2022, blood culture samples from different departments were incubated in the BD BACTEC™ system for 5 days. Species identification was performed using MALDI-TOF MS, and antimicrobial resistance patterns were determined by the VITEK2 system.

RESULTS

Out of 3197 species isolated from positive blood cultures, 38.7% were ESKAPE bacteria. Of these, 59.9% were found in blood culture samples taken from men, and the most affected age group was those aged >60 years. (70.6%). Staphylococcus aureus was the main BSI pathogen (26.3%), followed by Klebsiella pneumoniae (15.8%). Significant resistance rates were found, including 35% of Staphylococcus aureus being resistant to oxacillin and over 90% of Acinetobacter baumannii being resistant to carbapenems.

CONCLUSIONS

These results highlight the urgent need for antimicrobial stewardship programs to prevent incurable infections.

Predictors of mortality and severe illness from Escherichia coli sepsis in neonates

Neonatal Escherichia coli (E. coli) sepsis is increasing. There is limited data on the factors contributing to increased mortality and severity of illness in neonatal E. coli sepsis. A retrospective review of neonates (<30 days) admitted to a Level IV NICU in the United States from 2008 to 2022 diagnosed with E. coli bloodstream or cerebrospinal fluid infection was conducted. Primary outcome was defined as mortality from or severe illness during E. coli infection (defined as a need for inotropic support or metabolic acidosis). E. coli neonatal sepsis rate increased from 2008 to 2022 (average of 1.12 per 1000 live births). The primary outcome, which occurred in 57.4% of cases, was independently associated with prematurity, neutropenia, and thrombocytopenia. Ampicillin resistance was not associated with the primary outcome. GA, neutropenia, and thrombocytopenia but not ampicillin resistance, are associated with mortality or severe illness from E. coli sepsis.

Electrochemical platform for detecting Escherichia coli bacteria using machine learning methods

We present an electrochemical platform designed to reduce time of Escherichia coli bacteria detection from 24 to 48-h to 30 min. The presented approach is based on a system which includes gallium-indium (eGaIn) alloy to provide conductivity and a hydrogel system to preserve bacteria and their metabolic species during the analysis. The work is dedicated to accurate and fast detection of Escherichia coli bacteria in different environments with the supply of machine learning methods. Electrochemical data obtained during the analysis is processed via multilayer perceptron model to identify i.e. predict bacterial concentration in the samples. The performed approach provides the effectiveness of bacteria identification in the range of 102-109 colony forming units per ml with the average accuracy of 97%. The proposed bioelectrochemical system combined with machine learning model is prospective for food analysis, agriculture, biomedicine.

Bio-Responsive Sliver Peroxide-Nanocarrier Serves as Broad-Spectrum Metallo-β-lactamase Inhibitor for Combating Severe Pneumonia

Metallo-β-lactamases (MBLs) represent a prevalent resistance mechanism in Gram-negative bacteria, rendering last-line carbapenem-related antibiotics ineffective. Here, a bioresponsive sliver peroxide (Ag2 O2 )-based nanovesicle, named Ag2 O2 @BP-MT@MM, is developed as a broad-spectrum MBL inhibitor for combating MBL-producing bacterial pneumonia. Ag2 O2 nanoparticle is first orderly modified with bovine serum albumin and polydopamine to co-load meropenem (MER) and [5-(p-fluorophenyl)-2-ureido]-thiophene-3-carboxamide (TPCA-1) and then encapsulated with macrophage membrane (MM) aimed to target inflammatory lung tissue specifically. The resultant Ag2 O2 @BP-MT@MM effectively abrogates MBL activity by displacing the Zn2+ cofactor in MBLs with Ag+ and displays potent bactericidal and anti-inflammatory properties, specific targeting abilities, and great bioresponsive characteristics. After intravenous injection, the nanoparticles accumulate prominently at infection sites through MM-mediated targeting . Ag+ released from Ag2 O2 decomposition at the infection sites effectively inhibits MBL activity and overcomes the resistance of MBL-producing bacteria to MER, resulting in synergistic elimination of bacteria in conjunction with MER. In two murine infection models of NDM-1+ Klebsiella pneumoniae-induced severe pneumonia and NDM-1+ Escherichia coli-induced sepsis-related bacterial pneumonia, the nanoparticles significantly reduce bacterial loading, pro-inflammatory cytokine levels locally and systemically, and the recruitment and activation of neutrophils and macrophages. This innovative approach presents a promising new strategy for combating infections caused by MBL-producing carbapenem-resistant bacteria.

Multidrug-Resistant Escherichia coli Strains to Last Resort Human Antibiotics Isolated from Healthy Companion Animals in Valencia Region

Failure in antibiotic therapies due to the increase in antimicrobial-resistant (AMR) bacteria is one of the main threats to public and animal health. In recent decades, the perception of companion animals has changed, from being considered as a work tool to a household member, creating a family bond and sharing spaces in their daily routine. Hence, the aim of this study is to assess the current epidemiological situation regarding the presence of AMR and multidrug resistance (MDR) in companion animals in the Valencia Region, using the indicator bacteria Escherichia coli as a sentinel. For this purpose, 244 samples of dogs and cats were collected from veterinary centres to assess antimicrobial susceptibility against a panel of 22 antibiotics with public health relevance. A total of 197 E. coli strains were isolated from asymptomatic dogs and cats. The results showed AMR against all the 22 antibiotics studied, including those critically important to human medicine. Moreover, almost 50% of the strains presented MDR. The present study revealed the importance of monitoring AMR and MDR trends in companion animals, as they could pose a risk due to the spread of AMR and its resistance genes to humans, other animals and the environment they cohabit.

Antibiotic resistance in bloodstream isolates from high-complexity paediatric units in Madrid, Spain: 2013-2021

BACKGROUND

Antimicrobial resistance (AMR) has become a significant challenge in high-complexity healthcare settings.

AIM

To evaluate the prevalence of AMR in bloodstream isolates from high-complexity paediatric units in Spain over a nine-year period.

METHODS

A retrospective observational multicentre study was conducted in three tertiary hospitals, analysing bloodstream isolates from patients aged <18 years admitted to the paediatric intensive care, neonatology, and oncology-haematology units between 2013 and 2021. Demographics, antimicrobial susceptibility, and resistance mechanisms were analysed in two periods (2013-2017 and 2017-2021).

FINDINGS

In all, 1255 isolates were included. AMR was more prevalent in older patients and those admitted to the oncology-haematology unit. Multidrug resistance was observed in 9.9% of Gram-negative bacteria (GNB); 20.0% of P. aeruginosa vs 8.6% of Entero-bacterales (P < 0.001), with an increase in Enterobacterales from 6.2% to 11.0% between the first and the second period (P = 0.021). Difficult-to-treat resistance was observed in 2.7% of GNB; 7.4% of P. aeruginosa vs 1.6% of Enterobacterales (P < 0.001), with an increasing trend in Enterobacterales from 0.8% to 2.5% (P = 0.076). Carbapenem resistance among Enterobacterales increased from 3.5% to 7.2% (P = 0.029), with 3.3% producing carbapenemases (67.9% VIM). Meticillin resistance was observed in 11.0% of S. aureus and vancomycin resistance in 1.4% of Enterococcus spp., with both rates remaining stable throughout the study period.

CONCLUSION

This study reveals a high prevalence of AMR in high-complexity paediatric units. Enterobacterales showed a concerning increasing trend in resistant strains, with higher rates among older patients and those admitted to oncology-haematology units.

An overview of gram-negative bacteria with difficult-to-treat resistance: definition, prevalence, and treatment options

INTRODUCTION

Difficult-to-treat resistance (DTR) is a newly proposed resistance phenotype characterized by resistance to all first-line drugs. The emergence of DTR as a new resistance phenotype has significant implications for clinical practice. This new concept has the potential to be widely used instead of traditional phenotypes.

AREAS COVERED

This study carried out a detailed analysis about the definition, application, and evolution of various resistance phenotypes. We collected all the research articles on Gram-negative bacteria with difficult-to-treat resistance (GNB-DTR), analyzed the DTR in each region and each bacterial species. The advantages and doubts of DTR, the dilemma of GNB-DTR infections and the potential therapeutic strategies are summarized in the review.

EXPERT OPINION

Available studies show that the prevalence of GNB-DTR is not optimistic. Unlike traditional resistance phenotypes, DTR is more closely aligned with the clinical treatment perspective and can help with the prompt selection of an appropriate treatment plan. Currently, potential treatment options for GNB-DTR include a number of second-line drugs and novel antibiotics. However, the definition of first-line drugs is inherently dynamic. Therefore, the DTR concept based on first-line drugs needs to be continuously updated and refined, considering the emergence of new antibiotics, resistance characteristics, and pathogen prevalence in different regions.