Resistance Determinants Research Articles

Bats as Hosts of Antimicrobial-Resistant Mammaliicoccus lentus and Staphylococcus epidermidis with Zoonotic Relevance.

Bats are increasingly recognized as reservoirs for antimicrobial-resistant bacteria, playing a potential role in the dissemination of resistance genes across species and regions. In this study, 105 bats from 19 species in Portugal were sampled to investigate the presence, antimicrobial resistance, and genetic characteristics of Mammaliicoccus and Staphylococcus isolates. Thirteen Mammaliicoccus lentus and Staphylococcus epidermidis were recovered. Antimicrobial susceptibility testing revealed multidrug resistance in three isolates, with S. epidermidis carrying mph(C), msr(A), and dfrC genes, and M. lentus harboring salB, tet(K), and str. Notably, qacA was detected in S. epidermidis, highlighting its plasmid-associated potential for horizontal gene transfer to more pathogenic bacteria. Heavy metal resistance genes (arsB and cadD) were also identified, suggesting the role of environmental factors in co-selecting antimicrobial resistance. Molecular typing revealed the S. epidermidis strain as ST297, a clone associated with both healthy humans and invasive infections. These findings emphasize the need for monitoring bats as reservoirs of resistance determinants, particularly in the context of zoonotic and environmental health. The presence of mobile genetic elements and plasmids further underscores the potential for the dissemination of resistance. This study reinforces the importance of adopting a One Health approach to mitigate the risks associated with antimicrobial resistance.

Molecular characterization of putative antibiotic resistance determinant and virulence factors genes of Acinetobacter baumannii strains isolated from intensive care unit patients in Riyadh, Saudi Arabia.

Molecular characterization of putative antibiotic resistance determinant and virulence factors genes of Acinetobacter baumannii strains isolated from intensive care unit patients in Riyadh, Saudi Arabia.

Emergence of invasive Streptococcus dysgalactiae subsp. equisimilis in Spain (2012-2022): genomic insights and clinical correlations.

An increase in Streptococcus dysgalactiae subsp. equisimilis (SDSE) infections has been documented worldwide. This study aims to analyze invasive disease caused by SDSE (iSDSE) in adults over an 11-year period in Spain. We conducted a retrospective, laboratory-based study of iSDSE detected at Hospital Universitari de Bellvitge (HUB) from 2012 to 2022 (n = 89) and isolates collected in three Spanish hospitals in 2018 (n = 22). Clinical data from HUB were collected. Isolates were tested for antimicrobial susceptibility (European Committee on Antimicrobial Susceptibility Testing 2023), subjected to whole genome sequencing and analyzed for mobile genetic elements (MGEs). A mouse model was used to analyze virulence. iSDSE episodes at HUB occurred predominantly in older patients with comorbidities (particularly, diabetes, chronic heart disease, and malignancies). Whole genome sequencing revealed a high genetic diversity, with the most common lineages being CC15, CC17, and CC20. Various virulence factors, including the superantigen speG, were identified. Macrolides, lincosamides, and tetracyclines exhibited the highest resistance rates (>27%) and changed over time, linked to multiple MGEs. The mouse model highlighted the virulence of the CC20-stG62647 lineage, but these results were discordant with clinical data. iSDSE incidence is increasing and associated with older patients with comorbidities. Genetically, SDSE is diverse with a high capacity to integrate MGEs carrying resistance determinants. Mouse model studies showed the enhanced virulence of the CC20-stG62647 lineage. These findings underscore the need for ongoing surveillance of this emerging pathogen.

Biofilm associated growth inhibition of XDR Escherichia fergusonii strain ACE12 isolated from soil.

Biofilm associated growth inhibition of XDR Escherichia fergusonii strain ACE12 isolated from soil.

Comprehensive molecular epidemiology of Acinetobacter baumannii from diverse sources in Nigeria.

Acinetobacter baumannii, a Gram-negative bacterium, is a public health threat due to its role in nosocomial infections and increasing antibiotic resistance. In Nigeria, data on the molecular epidemiology of A. baumannii is scarce. This study investigates the genetic diversity and the presence of antimicrobial resistance determinants and virulence-related genes in whole-genome sequencing data of 189 Nigerian A. baumannii isolates deposited in public repositories. Genotypes were determined in-silico by multilocus sequence typing (MLST) and core genome MLST (cgMLST). Further, antimicrobial resistance (AMR) and virulence-related genes were analyzed. Most isolates (57.67%) originated from South-west Nigeria. Isolates of human origin accounted for 33.86%, while environmental sources comprised 6.87%, and 59.27% lacked information on the source of isolation. The cgMLST analysis revealed a multitude of genomic lineages circulating in Nigeria. The MLST Oxford scheme identified 44 sequence types (STs) in 62.96% of strains, with ST1089 being the most prevalent. The MLST Pasteur could assign 95.77% of strains to 49 STs, with ST2(IC2) and ST85(IC9) being the most dominant. Antimicrobial resistance analysis detected 168 genes encoding resistance to 12 antibiotic classes, with cephalosporin, carbapenem, and aminoglycoside resistance genes being the most prevalent. Notably, blaADC-79 (23.81%), blaOXA-23 (30.69%), and aph(3″)-Ib (30%) were frequent variants encountered. Seventeen multi-efflux system genes conferring resistance to multiple antibiotic classes were identified. Virulence gene analysis revealed 137 genes encoding six mechanisms, with genes for nutritional factors, effector delivery systems, and biofilm production being the most prevalent. This study highlights the diversity in AMR and virulence genes of A. baumannii in Nigeria, emphasizing the need for ongoing genomic surveillance to inform infection control and develop antibiotic resistance management strategies.

Emergence and evolution of rare ST592 bla NDM-1-positive carbapenem-resistant hypervirulent Klebsiella pneumoniae in China.

This study aimed to characterize the genomes of two rare ST592 Klebsiella pneumoniae isolates and to explore their evolution into carbapenem-resistant hypervirulent K. pneumoniae (CR-hvKp). The minimum inhibitory concentrations (MICs) were determined using a VITEK 2 compact system. Conjugation experiments were conducted using film matings. Whole-genome sequencing (WGS) was performed using the Illumina and Nanopore platforms. The antimicrobial resistance determinants were identified using the ABRicate program in the ResFinder database. Insertion sequences were identified using ISFinder and the bacterial virulence factors identified using the Virulence Factor Database (VFDB). The K and O loci were examined using Kleborate. Multilocus sequence typing (MLST) and replicon type identification were performed by the Center for Genomic Epidemiology. Conjugation-related elements were predicted using oriTfinder. The plasmid structure was visualized using Circos, and a possible evolutionary model was constructed using BioRender. Isolates KPZM6 and KPZM16 were identified as ST592 and KL57, respectively, and were collected from the same department. The antimicrobial susceptibility testing data revealed that KPZM16 possesses an extensively drug-resistant (XDR) profile, whereas KPZM6 is a susceptible K. pneumoniae. The hybrid assembly showed that both KPZM6 and KPZM16 have one pLVPK-like virulence plasmid carrying the rmpA, rmpA2, and iucABCD-iutA gene clusters. However, strain KPZM16 harbors one IncN plasmid carrying the carbapenem resistance genes bla NDM-1, dfrA14, and qnrS1. The results of the conjugation experiments demonstrated that the plasmid could be transferred to the recipient strain. It is possible that the NDM-1-producing plasmid was transferred from KPZM6 to KPZM16 via conjugation, leading to the formation of CR-hvKp. This is the first study in which complete genomic characterization of the rare NDM-1-producing ST592 K. pneumoniae clinical isolate was performed. This study provides a possible evolutionary hypothesis for the formation of CR-hvKp via conjugation. Early detection is recommended to avoid the extensive spread of this clone.

Comparative genomic analysis of clinical isolates of <i>Klebsiella pneumoniae</i> isolated from newborns with different outcomes of the infectious process in the neonatal period

Introduction. Some progress has been made in the study of the molecular mechanisms of antibiotic resistance, namely, genes and their variants have been identified that ensure the inactivation of beta-lactam antibiotics. Nevertheless, there is still a necessity for further studies of genetic diversity of nosocomial strains, prevalence of genetic determinants of resistance to other groups of antibiotics, virulence factors and realization of pathogenic potential by opportunistic microorganisms. Aim of the study was to compare the genetic profile of clinical isolates of Klebsiella pneumoniae isolated from newborns with different outcomes of the infectious process in the neonatal period. Materials and methods. Using whole-genome sequencing and bioinformatic analysis to search for determinants of resistance and virulence, 3 strains of K. pneumoniae were studied, 2 of which were isolated from the blood of a generalized form of infection, 1 from the feces of a newborn child. Results. K. pneumoniae strains belonged to sequence types (ST) ST23, ST14 and ST3559, and differed in genetic determinants of antibiotic resistance and virulence factors. At the same time, they all had the genetic determinants fimH, mrkA and iutA, which are associated with an increased ability to attach to substrates and transport aerobactin. Strain 222 of ST3559, which has the largest number of antibiotic resistance genes, contained the smallest number of virulence factor genes, and vice versa, strain 144 of ST23, in which the smallest number of antibacterial drug resistance genes was detected, contained the most virulence factor genes. Conclusions. Identification of K. pneumoniae strains that differ in the genetic profile of antibiotic resistance and virulence in neonatal hospital patients indicates a complex interaction between bacteria and the macroorganism, in which isolates with low pathogenic potential can cause serious infectious complications, and vice versa, when a highly virulent strain does not realize its pathogenic potential, as demonstrated in case of K. pneumoniae strains ST14, ST3559 and ST23, respectively. This highlights the difficulty of effectively predicting and managing infection risks in hospital operations.

Phenotypic and Genomic Assessment of Antimicrobial Resistance and Virulence Factors Determinants in Salmonella Heidelberg Isolated from Broiler Chickens.

Salmonella Heidelberg is frequently found in poultry and poultry products and is associated with antimicrobial resistance strains and infections and mortality in humans. Whole-genome sequencing is used to monitor and understand epidemiological factors related to antimicrobial resistance. This study aimed to characterize the phenotypic resistance and sequence the whole genome of Salmonella Heidelberg strains isolated from poultry products in Brazil. Fourteen Salmonella Heidelberg strains isolated from whole broiler chicken carcasses and portions in Brazil between 2013 and 2019 were used in this study. Genus confirmation was performed by polymerase chain reaction. The disk diffusion test was conducted to assess the phenotypical antimicrobial susceptibility of the strains. Whole-genome sequencing was carried out to investigate the presence of antimicrobial resistance genes, plasmids, multilocus sequence typing, and virulence-associated genes. A high frequency of phenotypic resistance to cephalosporins, tetracyclines, and sulfonamides was detected. All strains had mutations in gyrA and parC and contained the genes tet(A), fosA7, and sul. The presence of genes originating from Yersinia pathogenicity islands was also detected. This study identified a high frequency of antimicrobial resistance in Salmonella Heidelberg strains from broilers slaughtered in different regions of Brazil, all belonging to the same sequence type (ST15) and associated with multiple resistance and virulence genes. The presence of the Yersinia high-pathogenicity island was detected, indicating potential virulence. These findings highlight the importance of continuously monitoring antimicrobial resistance to control and prevent foodborne infections and maintain the efficacy of treatments for human salmonellosis.

Resistance to salt crystallization of thin-bedded or platy limestone from the town of Benkovac in Croatia

Purpose. This paper aims to show the petrographic microstructural properties of natural stone as a building material from Benkovac, which is exposed to the influence of sea salt crystallization on the Croatian Adriatic coast. Methods. The research is based on the graphical and statistical analysis of the results of polarization and electron microscopy, resistance to salt crystallization, ultrasound propagation velocity and uniaxial compressive strength testing. Three diffe-rent lithotypes of limestone – grainy, micritic and laminated are analyzed to evaluate their important petrographic properties that have impact on the durability when material is exposed to the salt crystallization. Findings. In the petrographic analysis, different characteristics are highlighted, especially those relevant to anisotropy of the structural features as lamination or layering. Besides determination of resistance to the salt crystallization, propagation of ultrasound direct P waves and uniaxial compressive strength are also tested. It is of scientific importance that a change in the internal structure of all samples, especially the laminated lithotype, is observed during the testing. The decrease of ultrasonic propagation velocity, decrease in compressive strength, and durability due to the action of crystallization pressure is a result of increase of the pore space and the fracturing along natural discontinuities such as lamination and layering. Originality. This paper is the first to deal with the resistance to salt crystallization of the Benkovac stone, especially from the point of view of its petrographic properties. It also deals with the new aspect of interpreting the durability results by combining different methods of evaluating properties that are related to each other. Practical implications. The knowledge gained in a specific area of the thin-bedded limestone of Benkovac can also be utilized in other places for better and effective protection and preservation of buildings, for which the same type of stone is quarried and used in construction.

Experimental temperature measurements with thermal transducers

The paper reviews experimental methods of temperature measurements using various types of thermometers, including liquid-glass thermometers, conductive resistance temperature transducers, and thermoelectric transducers. The principles of functioning, constructional features, working temperature ranges, and equations of resistance versus temperature are described. To improve the accuracy of measurements, methods of error correction are considered, in particular, parallax errors and incomplete immersion of the thermometer in the measuring medium, the necessity of introducing a compensation for temperature of free ends of thermocouples. The measurement procedure includes a step-by-step determination of temperature, resistance, and thermal electromotive force for conductive and thermoelectric transducers, followed by finding the temperature according to graduation tables. Examples of calculations using the procedure are described by comparing the tabulated and measured temperature values, which makes it possible to evaluate the effectiveness of using these temperature transducers when measuring certain temperatures in a thermostat. Examples of calculating the actual temperature based on the resistance of platinum and copper thermometers are provided, as well as the thermoelectric force of Chromel-Copel thermocouples.

Sludge amended soil induced multidrug and heavy metal resistance in endophytic Exiguobacterium sp. E21L: genomics evidences.

The emergence of multidrug-resistant bacteria in agro-environments poses serious risks to public health and ecological balance. In this study, Exiguobacterium sp. E21L, an endophytic strain, was isolated from carrot leaves cultivated in soil amended with sewage treatment plant-derived sludge. The strain exhibited resistance to clinically relevant antibiotics, including beta-lactams, fluoroquinolones, aminoglycosides, and macrolides, with a high Multi-Antibiotic Resistance Index of 0.88. Whole-genome sequencing revealed a genome of 3.06Mb, encoding 3894 protein-coding genes, including antimicrobial resistance genes (ARGs) such as blaNDM, ermF, tetW, and sul1, along with heavy metal resistance genes (HMRGs) like czcD, copB, and nikA. Genomic islands carrying ARGs and stress-related genes suggested potential horizontal gene transfer. The strain demonstrated robust biofilm formation, high cell hydrophobicity (> 80%), and significant auto-aggregation (90% at 48h), correlating with genes associated with motility, quorum sensing, and stress adaptation. Notably, phenotypic assays confirmed survival under simulated gastrointestinal conditions, emphasizing its resilience in host-associated environments. Comparative genomics positioned Exiguobacterium sp. E21L near Exiguobacterium chiriqhucha RW-2, with a core genome of 2716 conserved genes. Functional annotations revealed genes involved in xenobiotic degradation, multidrug efflux pumps, and ABC-type transporters, indicating versatile resistance mechanisms and metabolic capabilities. The presence of ARGs, HMRGs, and MGEs (mobile genetic elements) highlights the potential role of Exiguobacterium sp. E21L as a reservoir for resistance determinants in agricultural ecosystems. These findings emphasized the need for stringent regulations on sludge-based fertilizers and advanced sludge treatment strategies to mitigate AMR risks in agro-environments.

Breeding Productive Tree Genotypes: The Role of Hydraulic Resistance Along the Root-Stem-Leaf Continuum in Constraining Growth.

Breeding productive tree genotypes is crucial for sustainable forestry, yet the hydraulic architecture along root-stem-leaf continuum that constrains biomass yield remains unclear. Here, six poplar hybrid genotypes with contrasting yield were used to quantify whole-plant hydraulic resistance, its partitioning patterns, and anatomical traits along the continuum. We observed substantial genetic variations in hydraulic resistance parameters. Roots contributed the largest proportion of whole-plant hydraulic resistance (> 54%). Components along the continuum were well-coordinated, and hydraulic resistance of all components was strongly correlated with yield (R2 > 0.75), suggesting that hydraulic resistance is a strong predictor of yield. However, resistance partitioning patterns generally showed weak correlations with yield, with more productive genotypes partitioning a smaller proportion of resistance to leaves. Vessel diameter was a key determinant of hydraulic resistance at the root and leaf levels (R2 ≥ 0.75), and vessel length significantly influenced stem hydraulic resistance (R2 = 0.80). Additionally, genotypes with higher minor vein density and a lower ratio of palisade to spongy mesophyll thickness exhibited lower leaf resistance. Our results suggest that low hydraulic resistance throughout root-stem-leaf continuum is the functional basis for high yield, and the identification of key hydraulic and structural constraints will help overcome bottlenecks in breeding productive tree genotypes.

Salad Vegetables as a Reservoir of Antimicrobial-Resistant Enterococcus: Exploring Diversity, Resistome, Virulence, and Plasmid Dynamics.

This study investigates the occurrence, antimicrobial resistance (AMR) profiles, virulence factors, and plasmid composition of Enterococcus species isolated from salad ingredients in the United Arab Emirates (UAE). Four hundred salad vegetable items collected from local markets, over ten months through 2023, were screened, yielding an Enterococcus detection rate of 85.5% (342/400). E. casseliflavus was the most commonly identified species (50%), followed by E. faecium (20%) and E. faecalis (16%). Among 85 Enterococcus isolates tested for antimicrobial susceptibility, 55.3% displayed resistance to at least one agent, with 18.8% classified as multidrug-resistant (MDR). All isolates were not resistant to ampicillin, linezolid, teicoplanin, tigecycline, and high-level gentamicin. Intrinsic phenotypic resistance to vancomycin was found in E. gallinarum and E. casseliflavus, while low-level (<5%) ciprofloxacin and erythromycin resistance was sporadically detected in E. faecium and E. faecalis. Whole-genome sequencing (WGS) of 14 isolates (nine E. faecium, four E. faecalis, and one E. casseliflavus) unveiled a complex resistome. We report the first detection in salad vegetables of vancomycin resistance genes (vanC, vanXY-C2) in a vancomycin-susceptible E. faecalis isolate. Identifying tetM, ermB, and optrA genes in the studied isolates further underscored emerging resistance to tetracyclines, macrolides, and oxazolidinones. Concurrently, virulence gene analysis revealed 74 putative virulence factors, with E. faecalis harboring a higher diversity of biofilm-related and exoenzyme-encoding genes. One E. faecalis strain carried the cytolysin cluster (cylI, cylS, cylM), highlighting its pathogenic potential. Plasmid profiling identified 19 distinct plasmids, ranging from 3845 bp to 133,159 bp. Among the genome-sequenced isolates, mobilizable plasmids (47.3%) commonly carried AMR genes, especially tet(L) and tet(M), whereas conjugative plasmids (10.5%) did not harbor resistance determinants. These findings highlight that salad vegetables can still harbor and potentially transmit Enterococcus strains with clinically relevant resistance determinants and virulence traits. Enhancing foodborne AMR surveillance with WGS and targeted interventions is key to controlling its spread in the food.

Spatial multi-omics analysis of tumor-stroma boundary cell features for predicting breast cancer progression and therapy response.

The tumor boundary of breast cancer represents a highly heterogeneous region. In this area, the interactions between malignant and non-malignant cells influence tumor progression, immune evasion, and drug resistance. However, the spatial transcriptional profile of the tumor boundary and its role in the prognosis and treatment response of breast cancer remain unclear. Utilizing the Cottrazm algorithm, we reconstructed the intricate boundaries and identified differentially expressed genes (DEGs) associated with these regions. Cell-cell co-positioning analysis was conducted using SpaCET, which revealed key interactions between tumor-associated macrophage (TAMs) and cancer-associated fibroblasts (CAFs). Additionally, Lasso regression analysis was employed to develop a malignant body signature (MBS), which was subsequently validated using the TCGA dataset for prognosis prediction and treatment response assessment. Our research indicates that the tumor boundary is characterized by a rich reconstruction of the extracellular matrix (ECM), immunomodulatory regulation, and the epithelial-to-mesenchymal transition (EMT), underscoring its significance in tumor progression. Spatial colocalization analysis reveals a significant interaction between CAFs and M2-like tumor-associated macrophage (TAM), which contributes to immune exclusion and drug resistance. The MBS score effectively stratifies patients into high-risk groups, with survival outcomes for patients exhibiting high MBS scores being significantly poorer. Furthermore, drug sensitivity analysis demonstrates that high-MB tumors had poor response to chemotherapy strategies, highlighting the role of the tumor boundary in modulating therapeutic efficacy. Collectively, we investigate the spatial transcription group and bulk data to elucidate the characteristics of tumor boundary molecules in breast cancer. The CAF-M2 phenotype emerges as a critical determinant of immunosuppression and drug resistance, suggesting that targeting this interaction may improve treatment responses. Furthermore, the MBS serves as a novel prognostic tool and offers potential strategies for guiding personalized treatment approaches in breast cancer.

Chlorpromazine inhibits the plasmid-mediated oqxAB multidrug efflux pump in Escherichia coli isolates of Egyptian patients with utis

Over the past ten years, the prevalence of the OqxAB efflux pump, a plasmid-mediated quinolone resistance determinant, has increased among Escherichia coli (E. coli) isolates. The aim of this study was to genotypically and phenotypically investigate quinolone resistance of isolates and transferability of oqxAB genes by conjugation. One hundred E. coli isolates were collected from UTIs samples and identified using biochemical techniques and confirmed by VITEK-2 System. Antibiotic resistance of isolates was determined by disc diffusion method. MIC of levofloxacin was determined using the broth microdilution method. Efflux pump-mediated resistance was assessed using the chlorpromazine-based efflux-pump inhibitor microplate assay. PMQR genes (oqxA, oqxB) were detected by conventional PCR. A conjugation experiment was run to investigate the transferability of the quinolone resistance in having plasmids carrying oqxAB. DNA sequencing was performed for the identification of genes in both donors and tranconjugants. 80% of E. coli isolates were resistant for levofloxacin. Chlorpromazine significantly decreased the levofloxacin MIC values. oqxA and oqxB genes were detected in 44% and 39% of levofloxacin resistant isolates, respectively. The conjugation experiment revealed the transfer of resistance. MICs of levofloxacin in transconjugants carrying oqxAB significantly increased as compared to the parental recipients MICs. In conclusion, plasmid-mediated quinolone resistance linked to oqxAB may be a factor in rapid rise in and spread of bacterial quinolone resistance among Egyptian E. coli isolates. Chlorpromazine could inhibit efflux pump activity leading to decreased quinolones resistance improving their effectiveness in treatment infectious diseases.

Determination of Drought Resistance of Some Miniature Rose Varieties

It is important to identify plants with high drought resistance to minimize irrigation water in landscape areas. The experiment was carried out for six months at Çanakkale Onsekiz Mart University COSMOTLAB. The study aimed to determine the effects of four different irrigation levels [(S100), (S75), (S50), (S25)] on plant water consumption (ET), morphological and phenological parameters of four different miniature rose varieties (Mandarin, Orange Juwel, Zwergen Fee 09 and Zwerkönig 78) frequently used in landscape areas. As a result of the study, according to irrigation levels, the highest flower number values were observed in S100 and the lowest values were observed in 75% water restriction (S25). Water stress caused a decrease in the number of buds and a decrease in flower yield. In addition, it was observed that the flowering performance of the varieties was good even at 25% water restriction (S75) in the miniature rose varieties Mandarin, Orange Juwel and Zwerkönig 78 (except Z09). As a result, it can be said that Mandarin’s ET values (255.7-642.3 mm) are lower than other varieties, the highest plant height value under S50 is reached and when other parameters are evaluated together, it is more resistant to drought than other varieties.

Friction Prediction in Asphalt Pavements: The Role of Separated Macro- and Micro-Texture Parameters Under Dry and Wet Conditions

The characteristics of pavement texture are key determinants of skid resistance, directly affecting tire-pavement interactions. This study examines the relationship between separated pavement textures and friction coefficients under dry and wet conditions. Using 3D laser scanning, texture data were collected from 40 asphalt pavement sections in Nanchang. The data were processed through Fourier Transform and Butterworth filtering, enabling separation of macro- and micro-textures. Based on ISO 25178-2, 16 parameters—including Sa (Arithmetic Mean Height), Str (Texture Aspect Ratio), Vmc (Core Material Volume), and Ssk (Skewness)—were selected to represent macro- and micro-texture features. These parameters were analyzed against dry and wet friction coefficients, and regression models were developed to predict FDry and FWet. The results show significant effects of both macro- and micro-texture parameters on friction coefficients. Among macro-texture parameters, Sa and Vmc strongly correlate with FDry, suggesting that greater surface roughness and core material volume enhance friction in dry conditions. Conversely, Ssk negatively correlates with FDry, indicating that negatively skewed profiles improve skid resistance. Other macro-texture parameters also influence FDry to varying extents. For micro-texture, Sdc (Material Height Difference), Spd (Peak Density), and Vvv (Valley Void Volume) primarily affect FWet, with all showing significant positive correlations. This indicates that sharp peaks and void structures in micro-texture enhance skid resistance in wet conditions. The regression models effectively predict both friction coefficients, reducing field testing complexity and cost. These models provide an efficient tool for evaluating skid resistance and supporting pavement performance and maintenance management. This study highlights the distinct roles of macro and micro-texture in skid resistance, offering insights for optimizing pavement design and maintenance.

Emergence of Linezolid Resistance Genes optrA and cfr(D) in an Enterococcus saccharolyticus from Chicken.

Background: The emergence of linezolid resistance, mediated by genes such as optrA and cfr(D), poses a growing public health threat. While these genes have been detected in clinical and animal-derived Enterococcus species, their presence in underexplored species like Enterococcus saccharolyticus remains undocumented, leaving a significant gap in our understanding of their dissemination and stability. Method: E. saccharolyticus GXN23C125Es was screened for the presence of known linezolid resistance genes via PCR analysis. Conjugation and stability experiments were used to evaluate the transferability and stability of the resistance genes. The complete genome of GXN23C125Es was obtained using both the Illumina and Nanopore platforms. Results: We report the first identification of optrA and cfr(D) in GXN23C125Es from chicken feces in China. Whole-genome sequencing revealed multiple plasmid-borne resistance genes, including optrA, cfr(D), fexA, and erm(A). Stability testing demonstrated that optrA was highly stable, while cfr(D) was rapidly lost without selective pressure. Conclusions: These findings highlight E. saccharolyticus as a potential reservoir for linezolid resistance genes, underscoring the need for enhanced surveillance of resistance determinants in animal-associated bacteria. Understanding the dissemination dynamics of optrA and cfr(D) is crucial for mitigating their impact on public health and guiding antimicrobial resistance management strategies.

Correlation Between the Load-Bearing Capacity, Fire Resistance, and the Price of Glued Laminated Timber

In this study, a continuation of the research on the influence of the bearing capacity proof on the fire resistance of an element’s cross-section is presented; however, in this particular case, we focus on elements made of homogeneous glued laminated timber. This influence is assessed by considering the variations in the cross-section’s area and the strength class, which are at the end of this paper, expressed through the actual material price. In order to obtain numerical results, similarly to the case of softwood, the limit states method and reduced cross-section method were used. The main aim of this research was to determine the actual price of homogeneous glued laminated timber if the limit state of load-bearing capacity is met and a certain fire resistance is required. By reviewing the available literature, a certain lack of practical solutions that might provide an appropriate answer to this question is evident. Namely, it is a common practice in the engineering community that when a certain limit state of load-bearing capacity is met in the case of homogeneous glued laminated timber material, an acceptable assumption of 30 min (R30) fire resistance class is automatically fulfilled when fire acts on three sides of the cross-section. However, it was shown that this is not entirely correct and always applicable. The main results of this study are precisely related to the above notion and clearly indicate the importance of the bearing capacity proofing procedure in the determination of the GLT fire resistance. Following the numerical results makes it possible to make decisions about the optimal selection of the element’s cross-section and its influence on the required fire resistance, even in the early design phase. The correlation of the load limit state capacity proof with the corresponding fire resistance functions makes it possible, for any stress state case, to obtain the optimal price for timber material as their intersection point.

Genomic characterization of invasive Neisseria meningitidis in Spain (2011/12–2022/23): expansion of clonal complex 213 and the potential threat to 4CMenB vaccine strain coverage

ABSTRACT Invasive meningococcal disease (IMD) is associated with significant global morbidity and mortality and is addressed by conjugated polysaccharide and subcapsular vaccines. In Spain, data on 4CMenB vaccine strain coverage and antimicrobial susceptibility are limited. This study aimed to describe the genomic epidemiology, predict 4CMenB vaccine strain coverage, and assess antimicrobial susceptibility of 323 Neisseria meningitidis isolates causing IMD, collected from 57 Clinical Microbiology Laboratories in Spain over 12 years (2011/12–2022/23). Whole genome sequencing was performed to identify serogroup, clonal complex (cc), and antimicrobial resistance determinants. Vaccine strain coverage for serogroup B (MenB) isolates was predicted using the genetic Meningococcal Antigen Typing System approach. The most prevalent serogroups were B (57.9%), W (21.4%), C (10.4%), and Y (8.4%). MenB predominated throughout most seasons, except during the 2019/20 season when serogroup W peaked. Post-COVID-19 pandemic, MenB remained the most frequent (70.2%). Thirteen cc were identified among MenB isolates, with cc213 being the most prevalent (40.1%). Only 28.9% of MenB isolates were predicted to be covered by 4CMenB, with cc213 showing an exceptionally low coverage rate (5.3%) due to antigenic variants poorly targeted by the vaccine. Notably, cc213 was responsible for twice the proportion of MenB cases in 4CMenB-vaccinated versus unvaccinated. All isolates were susceptible to third generation cephalosporins, and 13.5% showed penicillin resistance. This study highlights the alarming prevalence of cc213 among MenB IMD cases in Spain and the limited 4CMenB coverage against this cc. The disproportionate representation of cc213 in vaccinated individuals underscores its potential to compromise vaccine effectiveness.