Search Results (2,121)

The growing threat of antibiotic-resistant bacteria necessitates the development of alternative antimicrobial strategies. This study investigated the design and evaluation of novel photodynamic agents based on Rose Bengal (RB) conjugated to two plant lectins, Pisum sativum agglutinin (PSA) and Laburnum anagyroides agglutinin (LABA), for targeted photodynamic inactivation of Gram-positive and Gram-negative bacteria. Both conjugates demonstrated high singlet oxygen quantum yields compared with free RB. Antibacterial efficacy was assessed against methicillin-sensitive and methicillin-resistant Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Salmonella paratyphi B under white LED illumination. PSA-RB exhibited superior bactericidal activity against all strains, whereas LABA-RB showed strain-specific efficacy, particularly against Gram-negative species. A binary mixture of PSA-RB and LABA-RB synergistically inactivated both MSSA and MRSA at RB concentrations of 6–10 nM and light doses of 3.1–7.8 J/cm². Complete killing of E. coli and S. paratyphi B was achieved at approximately half the RB concentrations needed for individual conjugates. PSA-RB activity primarily drove the inactivation of P. aeruginosa. Uptake studies revealed significantly enhanced accumulation of lectin-conjugated RB compared to free RB, with synergistic uptake observed for the conjugate mixture. These results suggest that lectin-based RB conjugates are effective antibacterial agents for photodynamic treatment, especially via the dual-targeting method. Full article

Methicillin-resistant Staphylococcus aureus (MRSA), a major global public health threat due to its broad resistance, urgently requires the development of new antibiotic alternatives. (‒)‒Epigallocatechin-3-gallate (EGCG) is considered a natural bioactive compound with anti-MRSA properties. The L-Lectin module of serine-rich adhesin for platelets (SraP) is considered an important target for blocking MRSA-infected hosts. This study aims to investigate the mechanism of action of EGCG against MRSA. Surface plasmon resonance (SPR), cell adhesion and invasion, biofilm formation, checkerboard assays, RNA sequencing (RNA-seq) and quantitative real-time polymerase chain reaction (qRT-PCR) were performed. The results showed that EGCG bound to SraP L Lectin with high affinity and effectively inhibited MRSA colonization. Additionally, EGCG significantly suppressed pyrimidine metabolism and downregulated related genes, thereby potentially inhibiting bacterial growth. It also markedly reduced the expression of multiple genes associated with β-lactam resistance and inhibited biofilm formation. A strong synergistic effect was observed between EGCG and the bactericidal agent ceftriaxone (CRO). When combined with 10 μg/mL EGCG, CRO required 75% less dosage and exhibited a prolonged antimicrobial effect. In conclusion, EGCG exerts anti-MRSA effects through multiple pathways and represents a promising candidate as an alternative therapeutic agent against MRSA infections. Full article

Background: Drug delivery against ciprofloxacin-resistant microbial strains is one of the most challenging areas of research in the pharmaceutical industry. The broad-spectrum antibiotic ciprofloxacin often faces challenges due to its poor bioavailability; thus, the activity of this drug is generally compromised against resistant strains. Traditional drug delivery systems, such as liposomes, are utilized to address this issue; however, niosomes have surfaced as a promising successor to their liposomal counterparts due to their superior attributes, such as enhanced stability and reduced toxicity. However, owing to environmental and toxicological concerns over commonly used chemical surfactants in niosomes, there is a pressing need to explore greener and safer alternatives. This study is focused on the application of sophorolipids (SLs), a biosurfactant that is synthesized by the yeast Starmerella bombicola, as a vesicular assembly for ciprofloxacin encapsulation. Methods: The SL-based niosomal formulation was characterized for particle size, zeta potential, and polydispersity index (PDI), while transmission electron microscopy (TEM) was employed to determine the morphology of niosomes. Agar well diffusion, broth dilution, and biofilm inhibition assays were performed to assess efficacy. Results: The niosomal formulations were successfully prepared; among them, the (+)vely charged formulation exhibited a more organized morphology, and their size and zeta potential values were found to be around ~371 nm and 63 mV for the blank niosomes (without the loaded drug) and ~269 nm and 51 mV for the ciprofloxacin-loaded niosomes. The minimum inhibitory concentration and biofilm inhibitory concentration against the MRSA strain were 5 µg/mL and 25 µg/mL, respectively, for the ciprofloxacin-loaded, (+)vely charged SL niosomes—for free ciprofloxacin these values were 40 µg/mL and 100 µg/mL—presenting remarkable potential for biofilm inhibition. Conclusion: This study highlights the promising therapeutic potential of SL-based ciprofloxacin-loaded niosomes against the emerging health threat of the MRSA strain. Full article

Background and Objectives: Secondary bacterial infection drives poor outcomes in older adults with COVID-19, but age-specific microbiology and its interaction with severity scores are not well defined. We characterized respiratory and pleural pathogens, resistance profiles, and their impact on day-5 SOFA/APACHE II in octogenarians versus younger adults. Methods: We performed a retrospective cohort study of adults with RT-PCR-confirmed coronavirus disease 2019 (COVID-19) at a tertiary infectious diseases center (≥80 years, n = 152; <65 years, n = 327). Respiratory and pleural samples were processed according to EUCAST standards. Identification employed matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). Pathogen distributions, susceptibilities, and rates of superimposed pneumonia, empyema, and bacteremia were compared by age, and associations between secondary pneumonia, day-5 SOFA/APACHE II, and 28-day mortality were analyzed. Results: Sputum was obtained in 67.1% of older and 65.7% of younger adults, with numerically higher culture positivity in older patients (73.5% vs. 65.1%). Pathogen spectra were similar, dominated by Streptococcus pneumoniae (24.0% vs. 24.3%), methicillin-susceptible Staphylococcus aureus (MSSA) (18.7% vs. 20.7%), methicillin-resistant Staphylococcus aureus (MRSA) (9.3% vs. 6.4%), and Klebsiella pneumoniae, including extended-spectrum β-lactamase (ESBL)-producing strains. Empyema was more frequent in octogenarians (7.9% vs. 3.1%), and pleural cultures were usually positive. Meropenem retained 100% activity against ESBL-producing K. pneumoniae and Pseudomonas in both strata. In ≥80-year-olds, superimposed pneumonia was associated with higher day-5 SOFA (6.6 vs. 5.5) and APACHE II (24.3 vs. 21.0) scores and markedly increased 28-day mortality (37.5% vs. 9.8%). Conclusions: In octogenarians with COVID-19, secondary bacterial pneumonia and empyema are frequent, microbiologically similar to younger adults, and strongly amplify organ dysfunction and mortality even with largely preserved carbapenem susceptibility. Full article

A 74-year-old man with type 2 diabetes presented with fever, urinary retention, and urinary difficulties. Initial abdominal Computed Tomography (CT) suggested acute pyelonephritis, but a low-density area in the prostate was overlooked. Following the confirmation of methicillin-resistant Staphylococcus aureus (MRSA) in blood and urine cultures, comprehensive screening for metastatic abscesses was necessitated. Diffusion-weighted whole-body imaging with background suppression (DWIBS) was utilized and clearly identified a prostatic abscess (PA), nephritis, urethritis, and subcutaneous cysts. These findings also raised suspicion of pyogenic vertebral osteomyelitis. Crucially, the PA, urethritis, subcutaneous cysts, and potentially the vertebral osteomyelitis were either overlooked or not detected by initial CT imaging. DWIBS allows for simultaneous whole-body screening and serves as a useful adjunctive tool for identifying minute abscesses, which may assist in detecting inflammatory foci that are sometimes overlooked by conventional imaging. Unlike CT, DWIBS avoids radiation and contrast agents, and is significantly more cost-effective than positron emission tomography-CT (PET-CT). DWIBS can thus serve as a useful, non-invasive tool for the early detection and exclusion of abscesses in other organs when metastatic abscess formation is suspected or cultures are positive for microorganisms causing metastatic abscesses. Full article

Staphylococcus aureus has been recognized as an important foodborne pathogen and methicillin-resistant S. aureus (MRSA) can cause fatal infections worldwide. Of great concern is that MRSA have been found in animals and non-healthcare settings; however, knowledge about the prevalence and genetic characteristics of S. aureus, especially MRSA from animals, retail meats and market shared shopping vehicles in the same district, is limited. In this study, we collected 423 samples including handrail swabs (n = 226) of shopping trolleys and baskets from 18 supermarkets, retail meats (n = 137) and swine nasal swabs (n = 60) between 2018 and 2020 in China. S. aureus isolates were isolated and identified by PCR, and then the mecA was used to confirm the MRSA. The antibiotic resistance and virulence genes among S. aureus were also analyzed, followed by whole genome sequencing (WGS). S. aureus isolates were widely distributed in shared shopping vehicles (8.0%, 18/226), retail meats (14.6%, 20/137) and swine (18.3%, 11/60). In total, 49 S. aureus were obtained and 20 of the 49 isolates were MRSA. We firstly reported a high prevalence of MRSA in shared shopping vehicles (7.5%, 17/226), followed by raw meats (2.2%, 3/137), and 44.4% (8/18) of the 18 supermarkets possessed MRSA-positive shopping vehicles. All 20 MRSA isolates were SCCmec IVa MRSA clones. Enterotoxin genes (sea/seb) associated with S. aureus food poisoning were present in 45.0% of the 20 S. aureus isolates from retail meats and 25.0% of the 20 MRSA isolates carried enterotoxin genes. Retail meats in this study carried ST6-MRSA, a common ST type of S. aureus from food-poisoning outbreaks in China. WGS showed that the MRSA from meats harbored enterotoxin gene sea and immune evasion genes (sak and scn) associated with human infections, and were clustered with previously reported MRSA isolates from animals and humans. The MRSA isolates carrying multiple virulence genes from shopping vehicles were also clustered with previously reported MRSA isolates from humans and animals, suggesting that the exchange of MRSA isolates might occur among different niches. Our results highlighted the risk of retail meats and shared shopping vehicles in spreading antimicrobial-resistant pathogens including MRSA. To our knowledge, this is the first report of the wide spread of MRSA in shared shopping vehicles in China. Full article

Foodborne pathogens remain a global public health concern, and antimicrobial resistance increases their impact. In mass-gathering cities such as Al-Madinah Al-Munawarah, contaminated ready-to-eat (RTE) fast foods can contribute to both local transmission and international spread. In this study, 300 RTE fast food samples, including shawarma, burgers, fried chicken, sandwiches, and salads, were collected from international franchises, local restaurants, and street vendors. Pathogens were identified using conventional culture combined with matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Antimicrobial susceptibility testing followed CLSI guidelines, and real-time PCR confirmed species identity and screened resistance determinants. Principal component analysis (PCA) and dendrogram clustering were used to assess diagnostic discrimination. Among the 300 samples, 129 (43.0%) were culture positive. The most common pathogens were Staphylococcus aureus (14.3%) and Escherichia coli (13.0%), followed by Salmonella spp. (9.0%) and Acinetobacter baumannii (6.7%). About 35% of S. aureus isolates were methicillin resistant (MRSA), and 85% of A. baumannii carried OXA-type carbapenemase genes. MALDI-TOF MS achieved 96.1% score-based identification and, with PCA, showed strong interspecies separation. PCR confirmed species identity and detected widespread resistance genes, with genotype–phenotype concordance of at least 80%. Overall, 60.5% of isolates were multidrug resistant. RTE fast foods in Al-Madinah represent reservoirs of MDR pathogens, including carbapenemase-producing A. baumannii. The combined use of MALDI-TOF MS and real-time PCR established a rapid and scalable workflow that provided reliable identification and resistance profiling in less than 24 h, compared with 48 to 72 h for conventional methods. This approach supports One Health surveillance in high-risk food settings and strengthens preparedness for mass gatherings. Full article

Lefamulin, a new, first-in-class pleuromutilin antibiotic, was recently approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMA) for the treatment of patients with community-acquired bacterial pneumonia (CABP). In this context, this review aimed to evaluate its activity against the most common pathogens causing this infection. A thorough search was performed in five databases (Embase, Scopus, Web of Science, PubMed, PubMed Central) from their inception to 14th of October 2025. Clinical and Laboratory Standards Institute (CLSI) and European Committee on Antimicrobial Susceptibility Testing (EUCAST) resistance breakpoints were applied. Out of a total of 224 articles identified, 11 were deemed eligible for inclusion. Resistance among Streptococcus pneumoniae, Haemophilus influenzae, and Staphylococcus aureus isolates was 0–2.6%, 0–2.4%, and 0–4.3%, respectively. Even among isolates with specific mechanisms of resistance, such as β-lactamase-producing H. influenzae and methicillin-resistant S. aureus, resistance was below 2.4% and 3.4%, respectively. Among isolates for which no breakpoints were available (Moraxella catarrhalis, atypical pathogens, Enterococcus spp., Streptococcus spp., Haemophilus spp., and Staphylococcus spp.), MIC₉₀ values were low. An exception were isolates belonging to Enterococcus spp., which displayed MIC₉₀ values ranging from 0.25 to >16 mg/L in the two studies with relevant data. Lefamulin demonstrated broad in vitro activity against key pathogens causing CABP, making it a considerable addition to the therapeutic options for such infections, especially in cases where first-line agents cannot be used for reasons such as allergy or previous failure. Full article

Blood culture remains the gold standard for identifying bloodstream infections caused by bacteria and fungi. Isolation of the culprit microorganism onto agar plates also facilitates antimicrobial susceptibility testing. The purpose of this study was to determine the contamination rates, pathogen profile, and antimicrobial resistance in a secondary healthcare setting in a two-year timeframe. In this study, data regarding blood cultures of the years 2023 and 2024 were retrospectively analyzed to address the above questions. Blood cultures were incubated for seven days before being discarded as negative. The percentage of positive blood cultures for both years was 14.3%. Most positive cultures contained Gram-positive cocci, with a prevalence of coagulase-negative Staphylococci. In descending order, 72.72% were coagulase-negative Staphylococci, 15.15% were Staphylococcus aureus, and 12.12% were Streptococci. One strain of S. aureus was methicillin-resistant (MRSA), and one strain of Enterococcus faecium was vancomycin-resistant (VRE). Of the Gram-negative rods, 78.3% were Enterobacterales. Of these, Escherichia coli, Klebsiella pneumoniae, and Proteus mirabilis were the top pathogens. The remainder comprised eight strains of Pseudomonas aeruginosa, four strains of Acinetobacter baumannii (one pandrug-resistant), three strains of Stenotrophomonas maltophilia, one strain of Sphingomonas paucimobilis, and one strain of Campylobacter jejuni. The isolated fungi comprised Candida parapsilosis, Candida glabrata, and Candida tropicalis. Of the isolated Escherichia coli strains, 39.5% were resistant to ciprofloxacin regardless of origin (outpatient or hospitalized patients). Outpatient samples were taken in a Hemodialysis Unit that collaborates with our laboratory, obtained from patients with fever or other signs of infection. Distinguishing true bacteremia from contamination remains challenging. The contamination rate in our study was quite high at 5.3%. Since there is no dedicated phlebotomy team in our healthcare setting, in light of our results, educational courses have been conducted to demonstrate the best practices for sample collection. Full article

Non-targeted methods (NTMs) using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) show promise in bacterial resistance detection, yet temporal variations in spectral features pose significant challenges. These proteomic patterns, which characterize bacterial phenotypes and pathological functions, may vary over time due to bacterial adaptation, virulence, or resistance mechanisms, resulting in large prediction uncertainties and potentially degrading NTM performance. We present a comprehensive screening method to detect temporal changes in MALDI-TOF spectral patterns, demonstrated using methicillin-resistant and -susceptible Staphylococcus aureus (MRSA/MSSA) isolates collected over several years. Our approach combines convolutional neural networks (CNNs) with statistical methods, including significance testing, kernel density estimation, and receiver operating characteristics for dataset shift detection. We employ Gradient-weighted Class Activation Mapping (Grad-CAM) for post hoc feature description, enabling biochemical characterization of temporal changes. This analysis reveals crucial insights into the dynamic relationship between spectral data patterns over time, addressing key challenges in developing robust NTMs for routine applications. Full article

This pilot study investigated the presence of methicillin-resistant Staphylococcus aureus (MRSA) and third-generation cephalosporin-resistant (3GC-R) Enterobacterales in conventionally kept domestic pigs and their environment across four districts in Rwanda. A total of 114 swabs (nasal, rectal, manure, dust) from 29 farms were collected and processed to isolate resistant bacteria. Thirty-two 3GC-R Enterobacterales were detected. Escherichia coli predominantly harboring bla_CTX-M group 1 β-lactamase genes, alongside Klebsiella pneumoniae isolates, all displaying extended-spectrum β-lactamase (ESBL) phenotypes. Four MRSA isolates, all belonging to clonal complex 398 and SCCmec type IV, the typical livestock MRSA, were recovered from nasal and environmental samples. Multidrug resistance was frequently observed. The co-occurrence of β-lactamase genes, non-β-lactam resistance genes, and virulence factors such as fimH and loci associated with extraintestinal pathogenic and enteropathogenic E. coli. The detection of both MRSA and 3GC-R Enterobacterales in the present study indicates pigs and their farm environments as reservoirs of WHO priority pathogens in Rwanda, highlighting a potential public health risk in the context of extensive human–animal–environment interaction. These findings emphasize the urgent need for integrated One Health surveillance and comprehensive AMR control strategies addressing both animal and environmental reservoirs to support Rwanda’s National Action Plan on Antimicrobial Resistance. Full article

The Infectious Diseases Society of America (IDSA) guidelines for community-acquired pneumonia (CAP) recommend pneumococcal urinary antigen testing (UAT) for a subset of inpatients admitted with pneumonia. Despite this, UAT testing is frequently performed on inpatients who do not meet the official IDSA criteria, and current evidence regarding antibiotic de-escalation in UAT-positive cases remains inconclusive. To explore this further, we conducted a retrospective cohort study examining antibiotic de-escalation patterns among hospitalized CAP patients who underwent UAT over a 60-day period during peak respiratory illness season (November and December, 2023). Patients with positive UAT results were compared to those who had negative UAT; the primary outcome was whether a positive UAT impacted antibiotic de-escalation prescribing. A total of 268 patients were analyzed—235 UAT-negative and 33 UAT-positive. Both groups were comparable in terms of disease severity, underlying health conditions, and readmission rates. Empiric therapy targeting Pseudomonas aeruginosa (P. aeruginosa) and methicillin-resistant Staphylococcus aureus (MRSA) was used in 40% of patients (36% in the UAT-positive group and 46% of the UAG-negative group). The use of atypical coverage, MRSA coverage, or anti-pseudomonal β-lactams was frequently de-escalated in both cohorts (p < 0.05); however, the UAT-positive group had significantly shorter durations of anti-pseudomonal therapy (p = 0.03) and anti-MRSA therapy (p = 0.02). Despite this, the UAT-positive group was more commonly given fluoroquinolones, such as levofloxacin or moxifloxacin, over narrow-spectrum β-lactams for final antibiotic coverage (p = 0.021). Overall, positive UAT appeared to support earlier discontinuation of anti-MRSA and anti-pseudomonal antibiotics; however, it did not impact fluoroquinolone use. Future antimicrobial stewardship efforts may benefit from promoting greater use of narrow-spectrum β-lactams in these patients. Full article

Diabetic wounds are typically difficult to heal. They are usually characterized by prolonged healing time and increased susceptibility to bacterial infection. Therefore, altering the wound microenvironment and improving antibacterial property are effective treatment strategies. In this study, a plant hydrogel with antimicrobial activity and pro-healing properties was designed to integrate silver nanoparticles (AgNPs) with antimicrobial activity into the natural Tofu Chai (Premna microphylla Turcz, PMT) hydrogel, which exhibits strong pro-healing ability and antibacterial infections on the wound surface. In vitro experiments showed that AgNPs-PMT had a significant killing effect on Methicillin-resistant Staphylococcus aureus (MRSA), with an antibacterial efficiency reaching 95.6%. In vivo results showed that AgNPs-PMT efficiently cleared bacteria at the wound site to promote the formation of neovascularization, collagen and granulation tissue, and facilitated wound healing in a diabetic wound model with MRSA infection. On the 11th day, the wound area was only 5.4% of its original size. Overall, AgNPs-PMT demonstrated favorable antibacterial effects against MRSA and showed great potential in the treatment of chronic diabetic wounds. Full article

Wastewater-based surveillance (WBS) is valuable for monitoring antimicrobial resistance (AMR). Staphylococci are key targets, as wastewater can facilitate gene transfer and resistance emergence. Data on WBS for population-level AMR in the Arabian-Gulf remain limited. This study assessed Staphylococcus diversity and resistance in Dubai wastewater. Samples were collected over eight months from nine community sites, two hospital nodes, and two wastewater treatment plants (WWTPs) and were analysed by culture-based method. Ninety-six Staphylococcus isolates were recovered from community, hospital, and WWTP influent, with no growth in effluent. Most isolates (n/N = 88/96) were coagulase-negative Staphylococcus (CoNS), spanning 15 species, dominated by S. saprophyticus, S. cohnii and S. sciuri. The only coagulase-positive Staphylococcus was S. aureus (n = 8) and the only species detected across all wastewater sources. Resistance was highest to benzylpenicillin (88%) and fusidic acid (82%), whereas all isolates remained susceptible to glycopeptides, tigecycline, and linezolid. Fusidic acid resistance was higher in community-wastewater isolates, whereas β-lactam resistance predominated in hospital-wastewater isolates. Sixty percent of CoNS were multidrug-resistant; methicillin resistance occurred in 37.5% of CoNS and 50% of S. aureus. Wastewater is a reservoir of diverse multidrug-resistant staphylococci, underscoring One Health relevance reflecting the potential for circulation between humans, animals, and the shared environment. WBS can support population-level AMR monitoring to inform public health and veterinary interventions. Full article

Background/Objectives: Deep eutectic solvents (DESs) have recently gained attention for their antimicrobial properties, particularly because they target both planktonic bacteria and biofilms. Among these, DESs based on α-hydroxy acids (αHAs) are of interest due to their inherent antibacterial properties and favorable biocompatibility. However, effects of the αHA molecular structure and hydrogen bonding ability within a DES formulation on biological activity has not yet been thoroughly investigated. Methods: This study systematically investigates DESs formed by combining glycolic acid, lactic acid or tartaric acid with either choline chloride or tetraethylammonium chloride. Results: All DESs demonstrate broad-spectrum antibacterial activity against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa and effectively inhibit biofilm formation while exhibiting low cytotoxicity toward 3T3-L1 fibroblasts. Conclusions: DES formation enhances antibacterial efficacy while attenuating cytotoxicity compared to the individual components, thereby decoupling bactericidal activity from toxicity. Physicochemical characterization confirms the formation of a eutectic phase and reveals that biological activity is primarily governed by acidity rather than by the specific αHA structure or eutectic strength. These results provide new insights into structure-function relationships in DESs and establish a design strategy for biocompatible, non-cytotoxic antimicrobial agents. Full article