Methicillin-resistant Research Articles

Characterization of bacteriophage vB_AbaS_SA1 and its synergistic effects with antibiotics against clinical multidrug-resistant Acinetobacter baumannii isolates.

Acinetobacter baumannii is a major cause of nosocomial infections globally. The increasing prevalence of multidrug-resistant (MDR) A. baumannii has become an important public health concern. To combat drug resistance, alternative methods such as phage therapy have been suggested. In total, 30 MDR A. baumannii strains were isolated from clinical specimens, and their antibiotic susceptibilities were determined. The Acinetobacter phage vB_AbaS_SA1, isolated from hospital sewage, was characterized. In addition to its plaque size, particle morphology, and host range, its genome sequence was determined and annotated. Finally, the antibacterial effects of phage alone, antibiotics alone, and phage/antibiotic combinations were assessed against the A. baumannii strains. Phage vB_AbaS_SA1 had siphovirus morphology, showed a latent period of 20 minutes, and a 250 PFU/cell (plaque forming unit/cell) burst size. When combined with antibiotics, vB_AbaS_SA1 (SA1) showed a significant phage-antibiotic synergy (PAS) effect and reduced the overall effective concentration of antibiotics in time-kill assessments. The genome of SA1 is a linear double-stranded DNA of 50,108bp in size with a GC content of 39.15%. Despite the potent antibacterial effect of SA1, it is necessary to perform additional research to completely elucidate the mechanisms of action and potential constraints associated with utilizing this bacteriophage.

Patient and provider costs of the new BPaL regimen for drug-resistant tuberculosis treatment in South Africa: A cost-effectiveness analysis.

Drug-resistant (DR) tuberculosis (TB) is typically characterized by resistance to a single or combination of first- and/or second-line anti-TB agents and commonly includes rifampicin-resistant (RR)-TB, multidrug-resistant (MDR)-TB, pre-extensively drug-resistant (pre-XDR)-TB and XDR-TB. Historically, all variations of DR-TB required treatment with second-line drugs which are less effective and more toxic than first-line options, have a longer treatment duration and are more expensive to both patients and providers. The World Health Organization (WHO) now recommends a new second-line 3-drug 6-month all-oral regimen consisting of bedaquiline, pretomanid, and linezolid referred to as BPaL. We estimate patient and provider costs of DR-TB treatment with BPaL compared to the current standard of care in South Africa. In coordination with South Africa's BPaL clinical access programme (CAP) we conducted an economic evaluation of A) patient costs through a cross-sectional patient cost survey and B) provider costs through a bottom-up costing analysis consisting of a retrospective medical record review (patient resource-use) and top-down financial record review (fixed/shared costs such as overhead). Across both costing perspectives, we compare costs of 1) BPaL, to current standard of care options including the 2) 9-11-month standard short oral regimen (SSOR) and 3) 18-21-month standard long oral regimen (SLOR). Eligible patients included those ≥14 years old with confirmed sputum pulmonary RR/MDR-TB, pre-XDR or XDR-TB. All costs are reported in 2022 United States Dollar (US$). A total of 72 patients were enrolled and completed the patient cost survey (41.7% on BPaL, 16.7% on the SSOR and 41.7% on the SLOR). Mean on-treatment patient costs were lowest among those on BPaL ($56.6) and increased four-fold among those on the SSOR ($228.1) and SLOR ($224.7). Direct medical patient costs were negligible across all treatment regimens, while direct non-medical patient and guardian costs for travel, food and nutritional supplementation accounted for the largest proportion of total costs ($54.6, $227.8 and $224.3 for BPaL, the SSOR and SLOR respectively). In assessing provider costs, a total of 112 medical records were reviewed (37.5%, 41.1% and 21.4% on BPaL, the SSOR and SLOR respectively). Total provider costs for producing a favorable treatment outcome (cured/completed treatment) were similar among those on BPaL ($4,948.7 per patient) and the SSOR ($4,905.6 per patient) with costs increasing substantially among those on the SLOR ($8,919.9 per patient). Based on incremental cost-effectiveness ratios (ICERs), at even the lowest willingness to pay (WTP) threshold, treatment with the new BPaL regimen was more cost-effective than current standard of care treatment options (ICER: $311.4 < WTP: $3,341). When using the newly recommended BPaL regimen, cost to patients decreased by 75% compared to current standard of care treatment options in South Africa. Due in part to higher resource-use within the BPaL CAP offsetting the shorter treatment duration, cost of treatment provision through BPaL and the 9-11-month SSOR were similar. However, when considering cost and treatment outcomes, BPaL was more cost-effective than other standard of care regimens currently available for DR-TB in South Africa.

The progress of Mycobacterium tuberculosis drug targets

Tuberculosis (TB) has been troubling humans for hundreds of years, is a highly infectious disease caused by Mycobacterium tuberculosis (Mtb) infection, Mtb can infect almost all organs of the body and is one of the deadly infectious diseases in the world. At present, the first-line treatment regimen has a long treatment cycle and is prone to multiple drug resistance. Anti-tuberculosis drugs and latent tuberculosis infection (LTBI) resistance are increasing year by year, and new targets and new bioactive compounds are urgently needed to treat this disease. This review focuses on the latest reported anti-TB drug targets and related compounds in recent years, reviews the current TB drug regimen and major defects, outlines the key drug targets developed to date in Mtb, and the current situation of newly discovered anti-TB resistant forms of drugs. To provide a reference for the research and development of new anti-TB drugs and bring new treatment strategies for TB patients.

Anti-Bacterial Action of Silver Nanoparticles Against MDR Bacteria Isolated from Hospital

Hospital-associated infections (HAIs) are considered to be a major source of infections in patients, especially in patients with permanently impaired immunity. There is alarming increase of multi drug resistant (MDR) bacteria and Antibacterial medication resistance has been deemed a serious hazard to public health by the World Health Organisation (WHO). The study aimed to isolate and identify main bacteria caused nosocomial infection, and trying to treatments by using nanoparticles. By measuring the antibacterial activity of the synthesised AgNPs using the agar disc diffusion technique, AgNPs demonstrated antibacterial properties against the Pseudomonas aeruginosa and Staphylococcus aureus MDR.

Synergistic pH-responsive MUC-1 aptamer-conjugated Ag/MSN Janus nanoparticles for targeted chemotherapy, photothermal therapy, and gene therapy in breast cancer

Drug resistance in cancer treatment, primarily attributed to the overexpression of the multidrug resistance (MDR) gene, significantly hampers the effectiveness of chemotherapy. This mechanism, driven by the increased production of P-glycoprotein (P-gp) efflux pumps, highlights the urgent need for innovative strategies to combat drug resistance in cancer patients. This study explores the application of antisense technology to suppress MDR gene expression, while addressing the challenges of instability and limited cellular uptake associated with antisense oligonucleotides. We synthesized Janus silver-mesoporous silica nanoparticles (Ag/MSN JNPs) using a sol-gel method, characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS), revealing uniformly sized, dumbbell-shaped nanoparticles with an average size of 285 ± 5.12 nm. Doxorubicin (DOX) was loaded into the porous structure of the mesoporous silica, and JNPs were functionalized with chitosan (CS) to incorporate P-gp antisense and a MUC-1 aptamer, serving as a pH-responsive gatekeeper. Our findings indicate that the Ap-As-DOX-JNPs achieved a remarkable 89 ± 0.59 % cell death in drug-resistant MCF-7/ADR cells after 48 h, alongside an 80 % reduction in P-gp expression. The combination of DOX, antisense technology, and photothermal therapy utilizing these JNPs demonstrates a promising strategy to effectively overcome drug resistance. Notably, normal MCF-7 cells exhibited reduced viability from 39.11 ± 1.12 % to 30.05 ± 1.07 % when treated with DOX-JNPs under near-infrared (NIR) irradiation. These results underscore the potential of utilizing MUC-1 aptamer-conjugated Janus nanoparticles in conjunction with chitosan as a gatekeeper to enhance the efficacy of chemotherapy, photothermal therapy, and gene therapy in overcoming multidrug resistance in cancer treatment.

Progressive cancer targeting by programmable aptamer-tethered nanostructures.

Scientific research in recent decades has affirmed an increase in cancer incidence as a cause of death globally. Cancer can be considered a plurality of various diseases rather than a single disease, which can be a multifaceted problem. Hence, cancer therapy techniques acquired more accelerated and urgent approvals compared to other therapeutic approaches. Radiotherapy, chemotherapy, immunotherapy, and surgery have been widely adopted as routine cancer treatment strategies to suppress disease progression and metastasis. These therapeutic approaches have lengthened the longevity of countless cancer patients. Nonetheless, some inherent limitations have restricted their application, including insignificant therapeutic efficacy, toxicity, negligible targeting, non-specific distribution, and multidrug resistance. The development of therapeutic oligomer nanoconstructs with the advantages of chemical solid-phase synthesis, programmable design, and precise adjustment is crucial for advancing smart targeted drug nanocarriers. This review focuses on the significance of the different aptamer-assembled nanoconstructs as multifunctional nucleic acid oligomeric nanoskeletons in efficient drug delivery. We discuss recent advancements in the design and utilization of aptamer-tethered nanostructures to enhance the efficacy of cancer treatment. Valuably, this comprehensive review highlights self-assembled aptamers as the exceptionally intelligent nano-biomaterials for targeted drug delivery based on their superior stability, high specificity, excellent recoverability, inherent biocompatibility, and versatile functions.

Synthesis, Biological Evaluation and Molecular Modeling Studies of Novel Tribromo-substituted Imidazole Analogs

IntroductionWith the increasing rate of antimicrobial resistance, there is an urgent demand of developing newer antimicrobial agents. In the present study we report a novel series of eighteen 1-(aryl)-2-(2,4,5-tribromo-1H-imidazol-1-yl)ethan-1-ones, which were synthesized and their spectral characterization was performed. The in-vitro studies of the compounds were carried out. Molecular modeling studies were performed on the most promising compound. The results obtained would help develop new compounds that may have broad-spectrum therapeutic effects. MethodsThe compounds were synthesized by reacting the corresponding bromo-imidazoles with substituted phenacyl bromides. The predictive ADME studies, MM-GBSA studies, and In-vitro studies were carried out for all the compounds. Binding mode analysis of the most active compounds was carried out. DFT investigations were also performed. Results and discussionsAll the synthesized compounds were found to be active against the different strains of microorganisms used in the in-vitro analysis. Binding mode analysis of the most active compounds were carried out in the active site of glucosamine-6-phosphate synthase (2VF5) and crystal structure of Mycobacterium tuberculosis InhA inhibited by PT70 (2X22). With the increasing global challenge of multi-drug resistance and the urgent need for new antimicrobial agents, these compounds show promising potential to meet emerging therapeutic demands in treating infectious diseases.

Diversity and Antifungal Susceptibilities of Yeasts from Mangroves in Hong Kong, China-A One Health Aspect.

While mangrove ecosystems are rich in biodiversity, they are increasingly impacted by climate change and urban pollutants. The current study provides first insights into the emergence of potentially pathogenic yeasts in Hong Kong's mangroves. Sediment and water samples were collected from ten urban and rural mangroves sites. Initial CHROMagarTM Candida Plus screening, representing the first application of this differential medium for water and soil samples collected from a non-clinical environment, enabled the rapid, preliminary phenotypic identification of yeast isolates from mangroves. Subsequent molecular profiling (ITS and/or 28S nrDNA sequencing) and antifungal drug susceptibility tests were conducted to further elucidate yeast diversity and drug resistance. A diversity of yeasts, including 45 isolates of 18 distinct species across 13 genera/clades, was isolated from sediments and waters from Hong Kong mangroves. Molecular profiling revealed a dominance of the Candida/Lodderomyces clade (44.4%), a group of notorious opportunistic pathogens. The findings also reveal a rich biodiversity of non-Candida/Lodderomyces yeasts in mangroves, including the first reported presence of Apiotrichum domesticum and Crinitomyces flavificans. A potentially novel Yamadazyma species was also discovered. Remarkably, 14.3% of the ubiquitous Candida parapsilosis isolates displayed resistance to multiple antifungal drugs, suggesting that mangroves may be reservoirs of multi-drug resistance. Wildlife, especially migratory birds, may disseminate these hidden threats. With significant knowledge gaps regarding the environmental origins, drug resistance, and public health impacts of pathogenic yeasts, urgent surveillance is needed from a One Health perspective. This study provides an early warning that unrestrained urbanization can unleash resistant pathogens from coastal ecosystems globally. It underscores the necessity for enhanced surveillance studies and interdisciplinary collaboration between clinicians, ornithologists, and environmental microbiologists to effectively monitor and manage this environmental health risk, ensuring the maintenance of 'One Health'.

Molecular insights and functional analysis of isocitrate dehydrogenase in two gram-negative pathogenic bacteria.

Klebsiella pneumoniae and Legionella pneumophila are common Gram-negative bacteria that can cause lung infections. The multidrug resistance of K. pneumoniae presents a significant challenge for treatment. This study focuses on isocitrate dehydrogenase (IDH), a key enzyme in the oxidative metabolic pathway of these two bacteria. KpIDH and LpIDH were successfully overexpressed and purified, and their biochemical characteristics were thoroughly investigated. The study revealed that KpIDH and LpIDH are homodimeric enzymes with molecular weights of approximately 70kDa. They are completely dependent on the coenzyme NADP+ and are inactive towards NAD+. KpIDH exhibits the highest catalytic activity at pH 8.0 in the presence of Mn2+ and at pH 7.8 in the presence of Mg2+. Its optimal catalytic performance is achieved with both ions at 55°C. LpIDH exhibited its highest activity at pH 7.8 in the presence of Mn2+ and Mg2+, respectively, and exhibits optimal catalytic performance at 45°C. Heat inactivation studies showed that KpIDH and LpIDH retained over 80% of their activity after being exposed to 45°C for 20min. Furthermore, we successfully altered the coenzyme specificity of KpIDH and LpIDH from NADP+ to NAD+ by replacing four key amino acid residues. This study provides a comprehensive biochemical characterization of two multidrug-resistant bacterial IDHs commonly found in hospital environments. It enhances our understanding of the characteristics of pathogenic bacteria and serves as a reference for developing new therapeutic strategies.

Cell-Based Screen Identifies a Highly Potent and Orally Available ABCB1 Modulator for Treatment of Multidrug Resistance.

Targeting ABCB1 is a promising strategy in combating multidrug resistance. Our cell-based phenotypic screening led to the discovery of novel triazolo[1,5-a]pyrimidone-based ABCB1 modulators. Notably, WS-917 was identified as a significant contributor to heightened sensitization of human colorectal adenocarcinoma cells (SW620/Ad300) to paclitaxel (IC50 = 5 nM). Mechanistic elucidation revealed that this compound substantially augmented intracellular paclitaxel and [3H]-paclitaxel, concurrently mitigating the efflux of [3H]-paclitaxel in SW620/Ad300 through the inhibition of ABCB1 efflux. The cellular thermal shift assay underscored its ability to stabilize ABCB1 through direct binding. Additionally, WS-917 induced stimulation of ABCB1 ATPase activity while exhibiting negligible inhibitory effect against CYP3A4. Remarkable was its capacity to enhance the sensitivity of SW620/Ad300 to paclitaxel, as well as the sensitivity of CT26/TAXOL to paclitaxel and PD-L1 inhibitor (Atezolizumab) in vivo, all achieved without inducing observable toxicity. The discovery of WS-917 holds promise for the development of more potent ABCB1 modulators.

ABCG2 Gene Expression in Non-Small Cell Lung Cancer.

Background/Objectives: ATP-binding cassette subfamily G member 2 [ABCG2/breast cancer resistance protein (BCRP)] contributes to mechanisms of multidrug resistance (MDR) and is a marker of side population (SP) cells in human cancers. The primary objective of this study was to investigate the impact of ABCG2 gene expression on the non-small cell lung cancer (NSCLC) development, course of cancer disease, and patient prognosis using publicly available data. Obtained results were supplemented with assessment of ABCG2 expression in blood of NSCLC patients. Methods: The dataset of lung cancer was analyzed utilizing the TIMER 2.0, UALCAN, TNMplot, MEXPRESS, cBioPortal, MethSurv, KM Plotter, STRING, and ShinyGO 0.80 databases. Blood samples from 50 patients were assessed using the real-time PCR method. Results: The ABCG2 gene was expressed at a low level in NSCLC, and did not correlate with clinical aggressiveness of lung cancer. Higher ABCG2 expression improved overall survival, but only in LUAD. In addition, CpG sites located on the CpG island affecting the NSCLC patient's prognosis were indicated. In the case of our own laboratory results, the study did not reveal any changes in the ABCG2 expression levels in blood collected from patients at different time points during the diagnostic-therapeutic procedure. In the in silico analysis, most ABCG2 protein interactors were associated with the development of drug resistance. Conclusions: ABCG2 appears to have a particularly significant impact on the survival of patients with lung cancer and on the effect of immunotherapy related to immune cell infiltration. Presented findings may support personalized medicine strategies based on bioinformatics findings.

Exogenous Methicillin-Resistant Staphylococcus aureus Endophthalmitis is Caused by Multidrug-Resistant Lineages that are Associated with Poor Outcomes

ABSTRACT Purpose To investigate the genomic epidemiology of methicillin-resistant Staphylococcus aureus (MRSA) endophthalmitis and correlate it with the presenting clinical features and outcomes. Methods Nine patients presenting with MRSA endophthalmitis from 2014 to 2022 were included. Phenotypic and genomic tests were used for strain characterization. Demographics, clinical presentation, treatment and outcomes were reviewed. Results The MRSA population was dominated by multidrug-resistant (MDR) strains within the clonal complex 5 (CC5) carrying an SCCmec type II genetic element (USA100-like strains). These strains carried genes that confer resistance to five antibiotic classes, in addition to mutations in topoisomerase genes (gyrA and parC) that resulted in resistance to all fluoroquinolones tested. Patients were mostly male (56%), with a median age of 82.7 years, and most had no recent history of extensive healthcare exposure. All cases were exogenous following ocular surgery (67%) or intravitreal injection (33%). The main exam findings were visual acuity ≤ hand motion, hypopyon (89%), and vitreous opacity (89%). Five patients (56%) showed improvement in visual acuity at 1 month following presentation, three (33%) at 3 months, and two (22%) at 6 months. Complications included evisceration (n = 1) and phthisis (n = 1). Patients who had pars plana vitrectomy within 48 hours of presentation had better clinical outcomes compared to those who did not. Conclusion Exogenous MRSA endophthalmitis is caused by MDR strains that resemble the hospital-acquired lineage USA100. These strains cause severe endophthalmitis in patients with no recent hospital/healthcare exposure.

Soloxolone N-3-(Dimethylamino)propylamide Restores Drug Sensitivity of Tumor Cells with Multidrug-Resistant Phenotype via Inhibition of P-Glycoprotein Efflux Function.

Multidrug resistance (MDR) remains a significant challenge in cancer therapy, primarily due to the overexpression of transmembrane drug transporters, with P-glycoprotein (P-gp) being a central focus. Consequently, the development of P-gp inhibitors has emerged as a promising strategy to combat MDR. Given the P-gp targeting potential of soloxolone amides previously predicted by us by an absorption, distribution, metabolism, excretion, and toxicity (ADMET) analysis, the aim of the current study was to experimentally verify their P-gp inhibitory and MDR reversing activities in vitro. Screening of soloxolone amides as modulators of P-gp using molecular docking and cellular P-gp substrate efflux assays revealed the ability of compound 4 bearing a N-3-(dimethylamino)propylamide group to interact with the active site of P-gp and inhibit its transport function. Blind and site-specific molecular docking accompanied by a kinetic assay showed that 4 directly binds to the P-gp transmembrane domain with a binding energy similar to that of zosuquidar, a third-generation P-gp inhibitor (ΔG = -10.3 kcal/mol). In vitro assays confirmed that compound 4 enhanced the uptake of Rhodamine 123 (Rho123) and doxorubicin (DOX) by the P-gp-overexpressing human cervical carcinoma KB-8-5 (by 10.2- and 1.5-fold, respectively (p < 0.05, unpaired t-test)) and murine lymphosarcoma RLS40 (by 15.6- and 1.75-fold, respectively (p < 0.05, unpaired t-test)) cells at non-toxic concentrations. In these cell models, 4 showed comparable or slightly higher activity than the reference inhibitor verapamil (VPM), with the most pronounced effect of the hit compound in Rho123-loaded RLS40 cells, where 4 was 2-fold more effective than VPM. Moreover, 4 synergistically restored the sensitivity of KB-8-5 cells to the cytotoxic effect of DOX, demonstrating MDR reversal activity. Based on the data obtained, 4 can be considered as a drug candidate to combat the P-gp-mediated MDR of tumor cells and semisynthetic triterpenoids, with amide moieties in general representing a promising scaffold for the development of novel therapeutics for tumors with low susceptibility to antineoplastic agents.

Metagenomic profiling of cecal microbiota and antibiotic resistome in rodents

The rodent gut microbiota is a known reservoir of antimicrobial resistance, yet the distribution of antibiotic resistance genes (ARGs) within rodent cecal microbial communities and the specific bacterial species harboring these ARGs remain largely underexplored. This study employed high-throughput sequencing of 122 samples from five distinct rodent species to comprehensively profile the diversity and distribution of ARGs and to identify the bacterial hosts of these genes. A gene catalog of the rodent cecal microbiome was constructed, comprising 22,757,369 non-redundant genes. Analysis of the microbial composition and diversity revealed that Bacillota and Bacteroidota were the dominant bacterial phyla across different rodent species, with significant variations in species composition among the rodents. In total, 3703 putative antimicrobial resistance protein-coding genes were identified, corresponding to 392 unique ARG types classified into 32 resistance classes. The most enriched ARGs in the rodent cecal microbiome were associated with multidrug resistance, followed by glycopeptide and elfamycin antibiotics. Procrustes analysis demonstrated a correlation between the structure of the microbial community and the resistome. Metagenomic assembly-based host tracking indicated that most ARG-carrying contigs originated from the bacterial family Oscillospiraceae. Additionally, 130 ARGs showed significant correlations with mobile genetic elements. These findings provide new insights into the cecal microbiota and the prevalence of ARGs across five rodent species. Future research on a wider range of wild rodent species carrying ARGs will further elucidate the mechanisms underlying the transmission of antimicrobial resistance.

Overview of Antimicrobial Resistant ESKAPEE Pathogens in Food Sources and Their Implications from a One Health Perspective.

Antimicrobial resistance is an increasing societal burden worldwide, with ESKAPEE (Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, Enterobacter species and Escherichia coli) pathogens overwhelming the healthcare sectors and more recently becoming predominantly a concern for their persistence in food and food industries, including agricultural settings and animal husbandry environments. The aim of this review is to explore the mechanisms by which the ESKAPEE group gained its multidrug resistance profiles, to analyse their occurrence in different foods and other related reservoirs, including water, and to address the current challenges due to their spread within the food production chain. Moreover, the repertoire of surveillance programmes available focused on monitoring their occurrence, common reservoirs and the spread of antimicrobial resistance are described in this review paper. Evidence from the literature suggests that restricting our scope in relation to multidrug resistance in ESKAPEE pathogens to healthcare and healthcare-associated facilities might actually impede unveiling the actual issues these pathogens can exhibit, for example, in food and food-related reservoirs. Furthermore, this review addresses the need for increasing public campaigns aimed at addressing this challenge, which must be considered in our fight against antimicrobial resistance shown by the ESKAPEE group in food and food-related sectors.

Clinical and Drug Resistance Characteristics of Providencia Infections

Background: Providencia is a G ram-negative bacillus that most frequently colonizes the urinary tract and is often resistant to many antimicrobials. This study aimed to evaluate the resistance patterns of Providencia spp. and clinical outcomes due to the paucity of data. Methods: A multi-center, descriptive, retrospective chart review of adult patients with Providencia spp. infections was conducted from 1 January 2020 to 31 May 2022. The primary outcome was to describe the drug resistance patterns of Providencia spp. isolates. This study’s secondary outcome was to evaluate the clinical outcomes of patients with Providencia spp. infections. Results: Of the 312 patients screened, 244 were excluded primarily for polymicrobial infections. The mean age was 70 years, and 39 (56.5%) were males. Of the 68 included cases, 46 (67.6%) were P. stuartii, 20 (29.4%) were P. rettgeri, and 2 (2.9%) were P. alcalifaciens. The most common infections were bacteremia 38 (55.8%), followed by 27 (39.7%) urinary tract infections and 3 (4.4%) wound infections. In this study, 45 patients (65.2%) had urinary catheters. The primary antibiotics used for treatment consisted of ceftriaxone (25 (36.2%)), cefepime (20 (29%)), and meropenem (10 (14.5%)). Only 5 of 68 (7.2%) cases were multidrug- resistant and required meropenem. In total, 19 patients (27.1%) died during their admission, but none were related to Providencia infections. A total of 10 of the 68 patients (14.5%) were readmitted within 30 days for reasons unrelated to the progression or recurrence of Providencia infections. Conclusions:Providencia bacteremia is predominantly seen in elderly patients. Third- generation cephalosporins remain an appropriate choice of antibiotics for Providencia spp. Providencia stuartii was the only species with multidrug resistance.

Quinolone and Tetracycline-Resistant Biofilm-Forming Escherichia coli Isolates from Slovak Broiler Chicken Farms and Chicken Meat

Escherichia coli isolates from intensive poultry production are associated with antimicrobial resistance and worldwide health problems. The aim of the study was to detect and evaluate the phenotypic and genotypic antimicrobial resistance, biofilm formation, phylogenetic typing, and virulence factors in E. coli isolates from the rectal swabs of chickens from two farms and swabs of chicken meat purchased from Slovakian food markets. Interpretative readings of minimal inhibitory concentration (MIC) revealed dominant resistance to ampicillin (&gt;50%) in both groups. We also detected higher resistance to ciprofloxacin (45%), tetracycline, ampicillin + sulbactam, and trimethoprim + sulfonamide (each &gt;30%). Here, 28.57% of the strains studied were multidrug-resistant (MDR). The formation of weak biofilms was confirmed in 8.8% of E. coli, while one of the strains obtained from chicken cloacal swabs was classified as a strong biofilm producer. The most frequently confirmed phylogenetic groups in E. coli were B1 and A1 in all groups. PCR detection revealed the presence of genes encoding tetracycline resistance (tetAB) and plasmid-mediated quinolone resistance (qnrABS), and Int1 (52.9%), Tn3 (76.5%), kpsMT II (8.8%), fimA (97.1%), cvaC (38.2%), and iutA (76.5%) genes in the strains studied. Our results demonstrate that chickens and chicken meat were the source of antibiotic-resistant, biofilm-forming, and virulent E. coli, representing a potential risk from the point of view of the One Health concept.

Virtual Screening Uncovers DspS Activators That Disperse Pseudomonas aeruginosa Biofilms.

Pseudomonas aeruginosa is the predominant bacterium found in many chronic biofilm infections. Over the past few decades, biofilm-related infections have posed a significant challenge to medical practice due to the increasing emergence of multidrug resistance. Cis-2-decenoic acid (CDA), a small molecule found in P. aeruginosa, has been shown to disperse biofilms formed by various bacteria and to work in synergy with common antibiotics. Despite that, the binding mechanism between CDA and the predicted cyclases/histidine kinases associated sensory extracellular (CHASE) domain of sensor protein DspS remains unknown in the absence of a crystallized protein structure. Moreover, the therapeutic potential of CDA is limited by its susceptibility to oxidative degradation and isomerization. In this work, we propose a structural model for the DspS CHASE domain. The resulting model displays an overall topology reminiscent of the sensor protein PcrK in Xanthomonas campestris. Through molecular dynamics simulations, a stable potential binding site for CDA was further identified. Virtual screening against the predicted site of DspS CHASE using our developed pipeline discovered two promising compounds, compounds 2 and 9, capable of dislodging 7-day P. aeruginosa biofilms at 50 μM without affecting bacterial growth. These compounds also enhanced the effects of ciprofloxacin against P. aeruginosa, reduced the survival of dispersed cells, and increased the expression of matrix-degrading enzyme genes pelA, pslG, and eddA. This study provides insights into CDA recognition by DspS and represents the first large-scale effort to uncover first-in-class DspS activators. At the same time, this work also underscores the effectiveness of a computational-aided drug discovery process in finding new activators, even without a known protein structure.

Boosting Expression of a Specifically Targeted Antimicrobial Peptide K in Pichia pastoris by Employing a 2A Self-Cleaving Peptide-Based Expression System.

Background/Objectives: The current epidemic of drug-resistance bacterial strains is one of the most urgent threats to human health. Antimicrobial peptides (AMPs) are known for their good activity against multidrug resistance bacteria. Specifically targeted AMPs (STAMPs) are a fraction of AMPs that target specific bacteria and maintain the balance of the healthy microbiota of a host. We reported a STAMP Peptide K (former name: peptide 13) for E. coli. The aim of this study was to effectively produce peptide K using methylotrophic yeast Pichia pastoris. Methods: Three inserts (sequence of peptide K (K), two copies of peptide K fused with 2A sequence (KTK), and two copies of peptide K fused with 2A and an extra α mating factor (KTAK)) were designed to investigate the effect of the number of repeats and the trafficking of peptide on the yield. Results: The yield from KTK was the highest-more than two-fold higher compared with K-implying the role of the 2A sequence in heterologous peptide expression apart from the co-translation. Then, the fermentation condition for KTK was optimized. The optimized yield of KTK was 6.67 mg/mL, suggesting the efficiency of the expression system. Selectivity, antibacterial activity, biocompatibility, and the stability of the fermentation product were equivalent to the chemically synthesized peptide. The actional mechanism of the fermentation product included membrane permeabilization and ROS induction. Conclusions: Together, our work provided a new perspective to augment the yield of the antimicrobial peptide in the microbial system, building a technological foundation for their large-scale production and expanding the market application of AMPs.

Role of migratory birds as a risk factor for the transmission of multidrug resistant Salmonella enterica and Escherichia coli to broiler poultry farms and its surrounding environment

Multidrug resistance (MDR) considered as global crisis facing poultry industry. Migratory birds play very important role in the dissemination of antimicrobial resistant pathogen during their fly way specially to poultry farms. Therefore, 750 samples from migratory birds and 300 samples from broiler chicken farms and its environment were collected during the winter seasons of five years (2019 to 2023). The samples were subjected to the isolation of Salmonella enterica and Escherichia coli with the detection of antimicrobial resistance (phenotypic and genotypic) with insight to the genetic similarity between the isolates from migratory birds and broiler chickens’ farms. Different members of Enterobacteriaceae were isolated; Salmonella enterica, Escherichia coli, Citrobacter, Enterobacter, Klebsiella, Proteus, Providencia, Serratia, Hafnia. 298 (28.4%) of S. enterica strains belonging to 27 serovars. S. Typhimurium, S. Kentucky, S. Enteritidis and S. Shangani were the common 4 serotypes between migratory birds and farms. Meanwhile, we found 489 (46.6%) isolates of E. coli belonging to 24 serogroups and O91, O128, O26, O125, O55, O103 and O159 were the common 7serogroups between migratory birds and farms samples. The majority of Salmonella (91.6%; 274 out of 298) and E. coli (92%; 450 out of 489) were MDR. The MDRI range of Salmonella and E. coli was 0.08- 1.The genetic similarity between the isolates of migratory birds and broiler chicken farms were detected by ERICPCR and hot map. This study suggests the continuous applications of surveillance programs for migratory birds and biosecurity measures in poultry farms.