Methicillin-resistant Research Articles

Arenicolide Family Macrolides Provide a New Therapeutic Lead Combating Multidrug‐resistant Tuberculosis

The emergence of multidrug‐resistant (MDR) and extensively drug‐resistant (XDR) strains of Mycobacterium tuberculosis (Mtb) poses a significant threat to health globally. During searching for new chemical entities regulating MDR‐ and XDR‐Mtb, chemical investigation of the black oil beetle gut bacterium Micromonospora sp. GR10 led to the discovery of eight new members of arenicolides along with the identification of arenicolide A (Ar‐A, 1), which was a previously reported macrolide with incomplete configuration. Genomic analysis of the bacterial strain GR10 revealed their putative biosynthetic pathway. Quantum mechanics‐based computation, chemical derivatizations, and bioinformatic analysis established the absolute stereochemistry of Ar‐A and arenicolides D‐K (Ar‐D‐K, 2‐9) completely for the first time. Biological studies of 1‐9 revealed their antimicrobial activity against MDR and XDR strains of Mtb. Ar‐A had the most potent in vitro antimicrobial efficacy against MDR‐ and XDR‐Mtb. Mechanistically, Ar‐A induced ATP depletion and destabilized Mtb cell wall, thereby inhibiting growth. Notably, Ar‐A exerted a significant antimicrobial effect against Mtb in macrophages, was effective in the treatment of Mtb infections, and showed a synergistic effect with amikacin (AMK) in a mouse model of MDR‐Mtb lung infection. Collectively, our findings indicate Ar‐A to be a promising drug lead for drug‐resistant tuberculosis.

Arenicolide Family Macrolides Provide a New Therapeutic Lead Combating Multidrug-resistant Tuberculosis.

The emergence of multidrug-resistant (MDR) and extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis (Mtb) poses a significant threat to health globally. During searching for new chemical entities regulating MDR- and XDR-Mtb, chemical investigation of the black oil beetle gut bacterium Micromonospora sp. GR10 led to the discovery of eight new members of arenicolides along with the identification of arenicolide A (Ar-A, 1), which was a previously reported macrolide with incomplete configuration. Genomic analysis of the bacterial strain GR10 revealed their putative biosynthetic pathway. Quantum mechanics-based computation, chemical derivatizations, and bioinformatic analysis established the absolute stereochemistry of Ar-A and arenicolides D-K (Ar-D-K, 2-9) completely for the first time. Biological studies of 1-9 revealed their antimicrobial activity against MDR and XDR strains of Mtb. Ar-A had the most potent in vitro antimicrobial efficacy against MDR- and XDR-Mtb. Mechanistically, Ar-A induced ATP depletion and destabilized Mtb cell wall, thereby inhibiting growth. Notably, Ar-A exerted a significant antimicrobial effect against Mtb in macrophages, was effective in the treatment of Mtb infections, and showed a synergistic effect with amikacin (AMK) in a mouse model of MDR-Mtb lung infection. Collectively, our findings indicate Ar-A to be a promising drug lead for drug-resistant tuberculosis.

Interference Between S. Aureus and P. Aeruginosa Clinical Isolates

General Background: Understanding microbial interactions between Pseudomonas aeruginosa and Staphylococcus aureus is crucial for clinical infections, as they often coexist and influence each other's growth and virulence. Specific Background: Both organisms are known for their ability to form biofilms and exhibit multidrug resistance (MDR), complicating treatment strategies in hospitalized patients. Knowledge Gap: Previous studies have explored the virulence of P. aeruginosa and S. aureus, but there is limited understanding of their direct in vitro interactions, particularly in protease and lipase production. Aims: The study examined the interaction between P. aeruginosa and S. aureus isolates in hospitalized patients' sputum, urine, and blood samples, focusing on virulence factors, biofilm formation, and antibiotic resistance patterns. Results: In Diyala, Iraq, 50 clinical isolates showed P. aeruginosa as protease producers, lipase producers, and biofilm producers, with significant MDR phenotypes in both species. Novelty: This study highlights the ability of P. aeruginosa to produce staphylolysin, offering novel insights into the antagonistic mechanisms that may suppress S. aureus in co-infections. Implications: The study emphasizes the significance of understanding microbial interactions in clinical infections, particularly in biofilm-associated MDR infections, to improve treatment outcomes and guide more effective therapeutic approaches. Highlights: P. aeruginosa staphylolysin inhibits S. aureus growth in vitro. Both bacteria produce biofilms and exhibit multidrug resistance. Microbial interactions impact infection severity and treatment strategies. Keywords: Microbial interactions, Pseudomonas aeruginosa, Staphylococcus aureus, Biofilm, Multidrug resistance

Molecular Typing of Pseudomonas aeruginosa Isolates Collected in Abidjan Hospitals (Côte d'Ivoire) Using the Multiple-Locus Variable Number of Tandem Repeats Method.

Background/objectives:Pseudomonas aeruginosa can cause community-acquired infections affecting various body sites. The present retrospective study investigated the genetic diversity of 173 isolates (166 clinical, 7 environmental) of P. aeruginosa collected from clinical pathology laboratories in Abidjan, Côte d'Ivoire (2001-2011). Methods: Multiple-Locus Variable Number of Tandem Repeats (VNTR) Analysis (MLVA) using 13 loci was applied to all isolates and compared to published MLVA data. The antibiotics status of the isolates was compiled when available and compared to published profiles. Results: Among 95 isolates analyzed for their antibiotics status, 14 displayed concerning resistance profiles: five multidrug-resistant (MDR) and nine extensively drug-resistant (XDR). MLVA typing revealed a high genetic diversity (>130 genotypes), with many genotypes represented by a single strain. Notably, thirteen clusters (≥4 related isolates) were observed. Some clusters displayed close genetic relatedness to isolates from France, Korea, and well-studied strains (ST560, LES and PA14). Comparative analysis suggested the presence of international high-risk MDR clones (CC233, CC111) in Côte d'Ivoire. Importantly, MLVA clustering revealed a close relationship of CC235-MDR strains with a locally identified cluster (group 9). Conclusions: These findings support MLVA as a reliable and cost-effective tool for low-resource settings, allowing the selection of relevant strains for future whole genome sequence analyses. This approach can improve outbreak investigations and public health interventions aimed at curbing MDR P. aeruginosa transmission within hospitals and at the national level.

MALDI-TOF MS profiling to predict resistance or biofilm production in gram-positive ESKAPE pathogens from healthcare-associated infections

Antimicrobial resistance and biofilm production in healthcare-associated infections is a health issue worldwide. This study aimed to identify potential biomarker peaks for resistance or biofilm production in ESKAPE pathogens using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility and biofilm production were assessed on selected isolates. Biomarker peaks were identified using MALDI Biotyper and ClinProTools software. Among resistant strains, 90.0 % were carbapenem-resistant Acinetobacter baumannii (CRAB), 39.0 % were methicillin-resistant Staphylococcus aureus (MRSA), 17.98 % were multidrug-resistant (MDR) Pseudomonas aeruginosa, 21.6 % were vancomycinresistant Enterococcus (VRE), and 2.55 % were carbapenem-resistant Enterobacterales (CRE). Biofilm production was 40.0 % in VRE and 45.8 % in MRSA. Although no potential biomarker peaks for biofilm production were detected, several potential biomarker peaks for drug resistance in VRE (n=5), MRSA (n=4), and MDR P. aeruginosa (n=4) were detected, suggesting avenues for the development of rapid diagnostic tools.

Surgical Site Infections: Risk Factors for Multiple Antibiotic Resistance in Abdominal Surgery

INTRODUCTION. Multidrug-resistant (MDR) organisms are increasingly becoming a major surgical site infection (SSI); however, the clinical outcomes and risk factors associated with resistant pathogens in general surgery remain poorly understood.THE AIM of the present research is to study the risk factors and consequences of infections in patients with SSI caused by antibiotic resistant pathogens with MDR.MATERIAL AND METHODS. A single-center, retrospective case-control study was carried out. The results of the examination and treatment of 50 patients with SSI + MDR, who made up the main group, and two control groups — non-MDR SSI and no SSI, 50 patients each, were analyzed. A total of 38 risk factors were used: pre- and surgical criteria, clinical, biochemical, instrumental data, postoperative complications and treatment features. The microbial landscape was studied in SSI+MDR. Single- and multivariate analysis was carried out, binary and multinomial logistic regression was performed. P-values <0.05 were considered significant at 95% CI.RESULTS. Significant risk factors were as follows: previous hospitalization, previous antibiotic therapy, terms of preoperative stay of the patient in the department, emergency surgery, class of surgery, decrease in the ratio of ALP/ ALPI, MEI and EMFC (p<0.01); elevated ASA score, obesity, low levels of plasma proteins and albumin, (p<0.05). Among the pathogens, there were more gram-negative enterobacteria (61%) than gram-positive ones (30.5%). Escherichia coli (36.3%) was the most commonly found bacterium, followed by Enterococcus faecium (9.09%), Morganella morganii (7.58%), Staphylococcus aureus (6%), and Pseudomonas aeruginosa (6%). In SSSI, Staphylococcus spp. prevailed. (>80%); in DSSI — Echerichia, Acinetobacter (>70%); and in OSSSI — Enterobacter spp., Acinetobacter and Citrobacter (>90%). SSI+MDR were characterized by serious surgical complications (Clavien Dindo Classification grade 3–5), wound dehiscences and OSSSI, reoperations (p<0.05).CONCLUSION. 1. The primary risk factors for multiple antibiotic resistance were as follows: previous hospitalization, previous antibiotic therapy, the duration of the patient’s preoperative stay in the department, emergency surgery, surgery class, reduced ALP/ALPI ratio, MEI and EMFC. In addition to the above, the following were also of great importance: increased ASA score, obesity, low plasma proteins, albumin.2. When identifying risk factors for multiple antibiotic resistance in surgical patients, the development of severe postoperative complications, sepsis and multiple organ failure can be predicted.3. Perioperative medical and preventive measures require a multidisciplinary approach involving the microbiologist, pharmacologist, immunologist, nutrition specialist, and other expert consultants.

Identifying Potential Natural Antibiotics from Unani Formulas through Machine Learning Approaches.

The Unani Tibb is a medical system of Greek descent that has undergone substantial dissemination since the 11th century and is currently prevalent in modern South and Central Asia, particularly in primary health care. The ingredients of Unani herbal medicines are primarily derived from plants. Our research aimed to address the pressing issues of antibiotic resistance, multi-drug resistance, and the emergence of superbugs by examining the molecular-level effects of Unani ingredients as potential new natural antibiotic candidates. We utilized a machine learning approach to tackle these challenges, employing decision trees, kernels, neural networks, and probability-based methods. We used 12 machine learning algorithms and several techniques for preprocessing data, such as Synthetic Minority Over-sampling Technique (SMOTE), Feature Selection, and Principal Component Analysis (PCA). To ensure that our model was optimal, we conducted grid-search tuning to tune all the hyperparameters of the machine learning models. The application of Multi-Layer Perceptron (MLP) with SMOTE pre-processing techniques resulted in an impressive accuracy precision and recall values. This analysis identified 20 important metabolites as essential components of the formula, which we predicted as natural antibiotics. In the final stage of our investigation, we verified our prediction by conducting a literature search for journal validation or by analyzing the structural similarity with known antibiotics using asymmetric similarity.

Resistance patterns, virulence determinants, and biofilm genes of multidrug-resistant Pseudomonas aeruginosa isolated from fish and fish handlers

Pseudomonas aeruginosa (P. aeruginosa) is an opportunistic bacterium that is widely distributed in aquatic environments and causes major economic losses in fish and public health hazards.This study aimed to identify the occurrence of P. aeruginosa in samples collected from fish and fish handlers, and to investigate the antimicrobial susceptibility, virulence determinants, and biofilm genes of P. aeruginosa isolates. A total of 276 samples were cross-sectionally collected from Nile tilapia (53), Golden grey mullet (52), Mediterranean horse mackerel (50), Striped red mullet (71), and fish handlers (50) at five different retail fish markets in Damietta Governorate, Egypt. Pseudomonas species (spp.) were biochemically identified in 57.9% of the total examined samples. Peudomonas aeruginosa were the most prevalent species isolated from the fish and human samples via PCR technique. Peudomonas aeruginosa isolates exhibited full resistance (100%) to tobramycin (TOB), gentamicin (CN), and colistin (CL), with a high level of susceptibility (88.5%) to imipenem (IPM) using the disk diffusion method. Most P. aeruginosa isolates (84.6%) exhibited drug resistance, with 61.5% were multidrug resistance (MDR) and 23.1% were extensive drug resistance (XDR). Most isolates had at least four virulence-associated genes (lasB, toxA, exoU, and oprL) and three biofilm genes (psIA, peIA, and lasR) by using uniplex PCR. The lasI, and rhlR Quorum Sensing (QS) genes were identified in 84.6% and 61.5% in the examined P. aeruginosa isolates, respectively. The highest mortality rate in Nile tilapia experimentally infected with P. aeruginosa isolate encoding most of virulent genes. Multivariate analyses revealed high heterogeneity among the examined isolates. This study revealed the emergence of virulent and drug resistant P. aeruginosa isolates in fish, poses high risks to consumers and food. Thus, strict hygienic measures should be considered when catching, handling, and storing fish, in addition to the routine application of antimicrobial susceptibility testing.

Prevalence, Virulence Genes, Drug Resistance and Genetic Evolution of Trueperella pyogenes in Small Ruminants in Western China.

Trueperella pyogenes is a significant opportunistic pathogen that causes substantial economic losses in animal agriculture due to its ability to infect various animal tissues and organs. Limited research has been conducted on the prevalence and biological characteristics of T. pyogenes isolated from sheep and goats. This study aimed to isolate T. pyogenes from clinical samples of sheep and goats in western China, examining genetic evolutionary relationships, antibiotic resistance, and virulence genes. Between 2021 and 2023, standard bacteriological methods were used to isolate and identify T. pyogenes from 316 samples (209 from goats and 107 from sheep) collected from 39 farms. Susceptibility to 14 antibiotics was tested using broth microdilution per CLSI guidelines, and PCR detected eight virulence genes. Whole-genome sequencing analyzed genetic relationships and gene carriage status in 39 isolates. The results indicated that 86 strains of T. pyogenes were isolated from 316 samples, yielding an isolation rate of 27.2% (goats n = 47, 22.5%; sheep n = 39, 36.4%). The virulence genes plo, cbpA, nanH, nanP, fimA, fimC, and fimE were present in 100%, 66.7%, 64.1%, 71.8%, 69.2%, 59.0%, and 82.1% of isolates, respectively, with none carrying the fimG gene. The dominant virulence genotype was plo/nanH/nanP/fimA/fimC/fimE. The isolates exhibited resistance to erythromycin (44.2%, 38/86), gentamicin (38.4%, 33/86), sulfamethoxazole/trimethoprim (37.2%, 32/86), tetracycline (32.6%, 28/86), and streptomycin (32.6%, 28/86), and low resistance to chloramphenicol (14.0%, 12/86), ciprofloxacin (7.0%, 6/86), penicillin (5.8%, 5/86), and clindamycin (4.7%, 4/86). All isolates were susceptible to cefotaxime, vancomycin, and linezolid. Among the 86 isolates, 37 (43.0%) displayed multidrug resistance (MDR) characteristics. The whole genome sequencing of 39 isolates identified eight types of resistance genes, including ant(2″)-Ia, ant(3″)-Ia, cmlA1, cmx, erm(X), lnu(A), sul1, and tet(W). Except for tet(W), erm(X), and sul1, the other resistance genes were reported for the first time in T. pyogenes isolated in China. The drug susceptibility test results and resistance gene detection for the isolated strains were consistent for tetracycline, erythromycin, gentamicin, and sulfisoxazole. Similar allelic profiles and genetic evolutionary relationships were found among isolates from different farms. This study highlights the antibiotic resistance status and virulence gene-carrying rate of Trueperella pyogenes, providing a basis for clinical medication.

Characterisation of Antimicrobial Resistance in Special-Fed Veal Production Environments.

Antimicrobial resistance (AMR) is one of the leading public health threats globally. AMR genes can be transferred between bacteria through lateral gene transfer, and AMR organisms can spread through environments by contaminated water, agriculture and animals. Thus, widespread environmental dissemination of bacteria and lateral gene transfer facilitate AMR transmission pathways. Farm environments in dairy and calf production are known to harbour AMR bacteria that pose a risk for food contamination and to workers in direct or indirect contact with animals. Escherichia coli is present in farm environments and is known to participate in lateral gene transfer, providing a good marker of resistance genes in each environment. In this study, E. coli from nine cohorts of calves was isolated at different time points from nine barns, nine trailers and one slaughterhouse environment in a single special-fed veal calf production facility. The antimicrobial susceptibility to 15 antimicrobials, classified as highly or critically important by the World Health Organization, was characterised for E. coli isolates using Kirby-Bauer disk diffusion. The highest proportion of isolates showing multidrug resistance was present in barn environments (51.7%), where calves were housed from their arrival at < 2 weeks of age until they were transported to slaughter. Additionally, 15 E. coli isolates were resistant to 11 of the 15 antimicrobials tested. Trailer and slaughterhouse environments had greater prevalence of resistance after accommodating calves, including resistance to third-generation cephalosporins. These data highlight the importance of calf environments in the dissemination of resistant bacteria and gives insight into where interventions could be most effective in combatting antimicrobial-resistant bacteria that could infect humans and livestock.

Antibiotic Resistance Pattern of Pathogens Isolated from Pediatric Patients during and after the COVID-19 Pandemic.

Background/Objectives: The present study aims to highlight the possible significant changes due to the COVID-19 pandemic in the resistance of pathogens involved in cases of pediatric infections. Methods: This study included children hospitalized in the Pediatric Intensive Care Unit, Surgery and Pediatrics from a tertiary teaching hospital, during and after the COVID-19 period (2020-2023). Results: The research included 845 samples collected during 2020-2023, from 685 pediatric patients. A total of 937 bacterial isolates were obtained, of which 509 isolates (54.32%) were Gram-negative bacteria. Around 30% of all the pathogens were multidrug-resistant (MDR), with a statistically significant increase post-pandemic, in the case of the MDR Escherichia coli strains (p < 0.05). A very high percentage of MDR Acinetobacter spp. isolates was found, with an important, but not statistically significant, increase in the post-pandemic period. The highest percentage of the MDR Gram-positive pathogens was registered in the case of S. aureus strains (31.80%). Over 20% of the Coagulase-negative Staphylococci (CoNS) strains isolated between 2020 and 2023 were MDR, with an important increase in the post-COVID-19 period. The proportion of carbapenem-resistant Gram-negative pathogens significantly decreased in the post-COVID-19 period compared with the COVID-19 period (p < 0.05), especially in the case of the Klebsiella spp. strains. Conclusions: Our findings revealed the increase in the post-COVID-19 period of the prevalence of MDR strains of Acinetobacter spp., CoNS, and Escherichia coli isolated in pediatric patient samples and a significant decline in the trend of the carbapenem-resistant Gram-negative pathogens, which may be due to the testing rate and to the specific pathology of the pediatric patients hospitalized in the two periods.

Antimicrobial resistance in plant endophytes associated with poultry-manure application revealed by selective culture and whole genome sequencing

Poultry manure is widely used as organic fertilizer in agriculture during the cultivation of crops, but the persistent high-level use of antibiotics in poultry production has raised concerns about the selection for reservoirs of antimicrobial resistance genes (ARGs). Previous studies have shown that the addition of poultry manure can increase the abundance of genes associated with resistance to tetracyclines, aminoglycosides, fluoroquinolones, sulfonamides, bacitracin, chloramphenicol, and macrolide-lincosamide-streptogramin in soil and plants. Understanding the microbial populations that harbor these ARGs is important to identify microorganisms that could enter the human food chain. Here, we test the hypothesis that environmental exposure to poultry manure increases the occurrence of antimicrobial resistance (AMR) in plant endophytes using selective culture, phenotypic Antibiotic Susceptibility Testing (AST), phylogenetic analysis, and whole genome sequencing (WGS). Endophytes from poultry manure treated Sorghum bicolor (L.) Moench plant root and stem samples showed increased phenotypic and genotypic resistance against multiple antibiotics compared to untreated controls. Comparison of AMR phenotype-to-genotype relationships highlighted the detection of multi-drug resistant (MDR) plant endophytes, demonstrating the value of genomic surveillance for emerging drug-resistant pathogens. The increased occurrence of ARGs in poultry manure-exposed endophytes highlights the need for responsible antibiotic use in poultry and animal farming to reduce contamination of ecological niches and transgression into endophytic plant microbiome compartments. It also emphasizes the requirement for proper manure management practices and vigilance in monitoring and surveillance efforts to tackle the growing problem of antibiotic resistance and preserve the efficacy of antibiotics for human and veterinary medicine.

Advanced Palladium Nanosheet-Enhanced Phototherapy for Treating Wound Infection Caused by Multidrug-Resistant Bacteria.

With the increasing spread of multidrug-resistant (MDR) bacteria worldwide, it is needed to develop antibiotics-alternative strategies for the treatment of bacterial infections. This work develops a multifunctional single-component palladium nanosheet (PdNS) with broad-spectrum and highly effective bactericidal activity against MDR bacteria. PdNS exerts its endogenous nanoknife (mechanical cutting) effect and peroxidase-like activity independent of light. Under near-infrared region (NIR) light irradiation, PdNS exhibits photothermal effect to produce local heat and meanwhile possesses photodynamic effect to generate 1O2; notably, PdNS has catalase-like activity-dependent extra photodynamic effect upon H2O2 addition. PdNS+H2O2+NIR employs a collectively synergistic mechanism of nanoknife effect, peroxidase/catalase-like catalytic activity, photothermal effect, and photodynamic effect for bacterial killing. PdNS+H2O2+NIR causes compensatory elevated phospholipid biosynthesis, disordered energy metabolism, increased cellular ROS levels and excessive oxidative stress, and inhibited nucleic acid synthesis in bacteria. In mice, PdNS+H2O2+NIR gives >92.7% bactericidal rates at infected wounds and almost the full recovery of infected wounds, and it leads to extensive down-regulation of proinflammatory pathways and comprehensive up-regulation of wound healing pathways, conferring elevated inflammation resolution and meanwhile accelerated wound repair. PdNS+H2O2+NIR represents a highly efficient nanoplatform for photoenhanced treatment of superficial infections.

Antibacterial Capabilities of Metallic Nanoparticles and Influencing Factors

ABSTRACTThe increase of antibiotic resistance in bacteria has become a major concern for successful diagnosis and treatment of infectious diseases. Over the past few decades, significant progress has been achieved on the development of nanotechnology‐based medicines for combating multidrug resistance in microorganisms. Among these, metallic nanoparticles (MNPs) hold great promise in addressing this challenge due to their broad‐spectrum and robust antimicrobial properties. This review illustrates the antibacterial activities of MNPs and further elucidates how different factors including synthesis method, size, shape, surface charge, pH, dose, type of capping or stabilizing agents of MNPs, and Gram‐type of the bacteria, impact their antibacterial activities, which are expected to promote the future development of more potent MNP‐based antibacterial agents.

Antibiotic prescribing patterns and risk of antibiotic-resistant infections and Clostridium difficile in Warfarin and Direct Oral Anticoagulant users: matched population-based cohort study

BackgroundWarfarin and Direct Oral Anticoagulant (DOAC) users may have more frequent antibiotic prescriptions than non-users. The aim of this study was to estimate rates of common and resistant infections, and antibiotic prescribing amongst warfarin and DOAC users versus non-users.MethodsThis matched retrospective cohort study used data from patients registered with General practices in England contributing to the Clinical Practice Research Datalink GOLD. We included 61,750 adults who initiated warfarin or a DOAC between 1st January 2011 and 31st December 2019, matched 1:1 to non-users. We estimated Incident Rate Ratios (IRR) and 95% Confidence Intervals for three common infections and all-cause antibiotic prescribing. We estimated hazard ratios (HRs) and 95% CIs for the risk of methicillin resistance Staphylococcus aureus (MRSA), other antibiotic-resistant organisms, or Clostridium difficile. We assessed the extent to which any of the effect of warfarin and DOAC use on antibiotic resistant infections or Clostridium difficile was mediated by antibiotic prescribing patterns.Results37,143 warfarin users and 24,607 DOAC users were matched 1:1 to non-users. Warfarin and DOAC users had greater relative consultation rates for respiratory, urinary, and skin infections. All-cause antibiotic prescribing was greater in warfarin and DOAC users (warfarin; adjusted IRR 1.47, 95% CI 1.45–1.50, DOAC; adjusted IRR 1.66, 95% CI 1.63–1.69). Largest effect sizes were observed for flucloxacillin (adjusted IRR 2.11, 95% CI 2.01–2.20), and erythromycin (adjusted IRR 2.32, 95% CI 2.00–2.70). Warfarin users had significantly higher risk of MRSA (adjusted HR 1.68, 95% CI 1.38–2.05) and hospital admission with antibiotic resistant infections (adjusted HR 1.91, 95% CI 1.11–3.30). DOAC users had significantly higher risk of MRSA (adjusted HR 1.57, 95% CI 1.20–2.06), hospital admission with antibiotic resistant infections (adjusted HR 2.13, 95% CI 1.61–2.82), and Clostridium difficile (adjusted HR 1.45, 95% CI 1.10–1.92). We found little evidence to suggest that the increased risks of studied outcomes were mediated by rates of antibiotic prescription.ConclusionWarfarin and DOAC use was associated with greater rates of infection consultations, all-cause antibiotic prescribing, antibiotic resistant infections, and Clostridium difficile, but there was little evidence that antibiotic prescribing rates mediated risk of resistant infections or Clostridium difficile.

Disproportionality analysis of the safety profile of rufinamide in the real world: an evaluation of the FDA Adverse Event Reporting System database

ABSTRACT Background Rufinamide (RUF) is an antiepileptic drug recently introduced for managing seizures in Lennox-Gastaut syndrome (LGS), but its adverse reactions are not well understood. This study aims to evaluate RUF’s safety profile using data from the FDA Adverse Event Reporting System (FAERS). Methods Disproportionality analysis was conducted to assess RUF-associated adverse drug events (ADEs), using reporting odds ratio (ROR), proportional reporting ratio (PRR), Bayesian confidence propagation neural network (BCPNN), and multi-item gamma-Poisson shrinker (MGPS). Results We collected 338 ADE reports related to RUF. Nervous system disorders were the most frequently reported signals, and several new ADEs were detected, including atonic seizures, sudden unexplained death in epilepsy, seizure clusters, multi-drug resistance, and Stevens-Johnson syndrome. Nearly half of the ADEs in pediatric patients were psychological or neurological. Disproportionality analysis within 4 weeks of treatment showed high RORs for QT shortening, sudden death, and atonic seizures. Conclusions Our study revealed prospective signals of new ADEs linked to RUF as well as revealed that both prescribers and patients were more conscious of the risks involved in its clinical use.

Tandem mobilization of anti-phage defenses alongside SCCmec elements in staphylococci

Recent research has identified multiple immune systems that bacteria use to protect themselves from viral infections. However, little is known about the mechanisms by which these systems horizontally spread, especially among bacterial pathogens. Here, we investigate antiviral defenses in staphylococci, opportunistic pathogens that constitute leading causes of antibiotic-resistant infections. We show that these organisms harbor a variety of anti-phage defenses encoded within or near SCC (staphylococcal cassette chromosome) mec cassettes, mobile genomic islands that confer methicillin resistance. Importantly, we demonstrate that SCCmec-encoded recombinases mobilize not only SCCmec, but also tandem SCC-like cassettes enriched in genes coding for diverse defense systems. Further, we show that phage infection stimulates cassette mobilization (i.e. excision and circularization). Thus, our findings indicate that SCC/SCCmec cassettes not only spread antibiotic resistance but can also play a role in mobilizing anti-phage defenses.

Synthesis and evaluation of novel tetrahydroisoquinoline-benzo[h]chromen-4-one conjugates as dual ABCB1/CYP1B1 inhibitors for overcoming MDR in cancer

The emergence of multidrug resistance (MDR) in malignant tumors is one of the major threats encountered currently by many chemotherapeutic agents. Among the various mechanisms involved in drug resistance, P-glycoprotein (P-gp, ABCB1), a member of the ABC transporter family that significantly increases the efflux of various anticancer drugs from tumor cells, and the metabolic enzyme CYP1B1 are widely considered to be two critical targets for overcoming MDR. Unfortunately, no MDR modulator has been approved by the FDA to date. In this study, based on pharmacophore hybridization, bioisosteric and fragment-growing strategies, we designed and synthesized 11 novel tetrahydroisoquinoline-benzo[h]chromen-4-one conjugates as dual ABCB1/CYP1B1 inhibitors. Among them, the preferred compound A10 exhibited the best MDR reversal activity (IC50 = 0.25 μM, RF = 44.4) in SW620/AD300 cells, being comparable to one of the most potent third-generation P-gp inhibitors WK-X-34. In parallel, this dual ABCB1/CYP1B1 inhibitory effect drives compound A10 exhibiting prominent drug resistance reversal activity to doxorubicin (IC50 = 4.7 μM, RF = 13.7) in ABCB1/CYP1B1-overexpressing DOX-SW620/AD300-1B1 resistant cells, which is more potent than that of the CYP1B1 inhibitor ANF. Furthermore, although compound A2 possessed moderate ABCB1/CYP1B1 inhibitory activity, it showed considerable antiproliferative activity towards drug-resistant SW620/AD300 and MKN45-DDP-R cells, which may be partly related to the increase of PUMA expression to promote the apoptosis of the drug-resistant MKN45-DDP-R cells as confirmed by proteomics and western blot assay. These results indicated that the tetrahydroisoquinoline-benzo[h]chromen-4-one conjugates may provide a fundamental scaffold reference for further discovery of MDR reversal agents.

Vesicle-Transported Multidrug Resistance as a Possible Therapeutic Target of Natural Compounds.

A key role of extracellular vesicles (EVs) is mediating both cell-cell and cell-stroma communication in pathological/physiological conditions. EVs from resistant tumor cells can transport different molecules like P-glycoprotein (P-gp), acting as a shuttle between donor and recipient cells, resulting in a phenotypic change. The aim of our work was to isolate, characterize, and inhibit the release of EVs in two multidrug resistance (MDR) cancer models: MCF-7R (breast cancer cell line) and HL-60R (acute myeloid leukemia cell line). The existence of P-gp in EVs from MDR cells was confirmed by Western blotting assays. The characterization of EVs was carried out by evaluating the size using NTA and the presence of specific markers such as CD63, Hsp70 and Syntenin. The ability of HL-60R and MCF-7R to perform horizontal transfer of P-gp via EVs to sensitive cells was assessed using three different methods. The acquisition of resistance and its inhibition in recipient cells was confirmed by MTS 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay. Our data showed that cell lines (MDR) release P-gp-loaded EVs, unlike sensitive cells. The acquisition of resistance determined by the incorporation of P-gp into the membrane of sensitive cells was confirmed by the reduced cytotoxic activity of doxorubicin. Natural compounds such as curcumin, lupeol, and heptacosane can block vesicular transfer and restore the sensitivity of HL-60 and MCF-7 cells. Our study demonstrates that natural inhibitors able to reverse this mechanism may represent a new therapeutic strategy to limit the propagation of the resistant phenotype.

A TaqMan real-time PCR assay for detection of qacEΔ1 gene in Gram-negative bacteria

The transfer of biocide and antibiotic resistance genes by mobile genetic elements is the most common mechanism for rapidly acquiring and spreading resistance among bacteria. The qacEΔ1 gene confers the resistance to quaternary ammonium compounds (QACs). It has also been considered a genetic marker for the presence of class 1 integrons associated with multidrug-resistant (MDR) phenotypes in Gram-negative bacteria. In this study, a TaqMan real-time PCR assay was developed to detect the qacEΔ1 gene in Gram-negative bacteria. The assay has a detection limit of 80 copies of the qacEΔ1 gene per reaction. No false-positive or false-negative results have been observed. Simultaneous amplification and detection of the 16S rRNA gene is performed as an endogenous internal amplification control (IAC). The TaqMan real-time PCR assay developed is a rapid, sensitive, and specific method that could be used to monitor resistance to QACs, the spread of class 1 integrons, and the prediction of associated MDR phenotypes in Gram-negative bacteria.