Multidrug-resistant bacteria contribute to core bacterial community and ARGs persistence during full-scale pharmaceutical wastewater treatment.

Enterococcus is a potential reservoir associated with antibiotic resistance in the "environment-animal-human" chain of dairy farms: Evidence from ecological linkage.

Salmonella spp. in deep tissue lymph nodes of bovine origin: A systematic review and meta-analysis.

Pseudomonas aeruginosa is a multidrug-resistant pathogen, highly prevalent in ICU patients and is a rising concern globally. Multidrug resistance (MDR) and virulence of P. aeruginosa has been a major reason linked to the high rates of mortality in both developed and non-developed countries. The study focused specifically on main structural outer membrane proteins mainly oprI and oprL due to their significant role on both virulence and MDR by assessing their MDR from the isolates collected from various healthcare settings in Lahore, Pakistan. A total of 65 isolated were collected from different tertiary care hospitals of Lahore, Punjab. All isolates were identified and characterized using conventional methods. MDR patterns were assessed through disk diffusion method in accordance with CLSI 2024 guidelines. Detection of virulence genes (oprI and oprL) was performed using PCR amplification. Statistical and in silico analysis was performed to analyse the prevalence of P. aeruginosa and identification of potential vaccine targets provide alternative treatment strategies against infections caused by it. Out of all 65 isolates, total of 52 isolates was reportedly positive with P. aeruginosa and showed 100% resistance to β-lactams with high susceptibility to cephalosporins and fluoroquinolones. Multidrug resistance was reported in 70% isolates of P. aeruginosa. All isolates (100%) harbored the oprL gene while the oprI gene was detected in 85.5% of isolates. In silico characterization revealed strong binding B and T cell epitopes with 100% conservancy as potential multi-epitope candidates that warrant further in vivo and in vitro validation to overcome deadly infections caused by P. aeruginosa. In conclusion, MDR and virulence gene characterization by both molecular and computational methods will aid in developing multi-epitope vaccine candidate that can be tested in vitro and in vivo to overcome MDR and rising mortality rates in Pakistan.

Antimicrobial resistance (AMR) is considered one of the greatest challenges to global health and a direct threat to human, animal, and environmental health. Thus, the objective of this survey was to characterise the antimicrobial susceptibility profile of Enterobacterales isolated from Gallus gallus domesticus (commercial laying hens [CLH] and free-range hens [FRH]) in the Caatinga biome. Cloacal swabs were collected from 165 CLH and 165 FRH in the states of Paraíba and Rio Grande do Norte, covered by the Caatinga biome. Bacterial isolation and antimicrobial susceptibility testing were performed, and phenotypic and genotypic detection of extended-spectrum β-lactamases (ESBLs) and cephamycins (AmpC) was carried out, as well as multidrug resistance (MDR) was calculated. Enterobacterales were detected in 92.1% CLH and in 100% FRH. Escherichia coli was the most frequent isolate, followed by Klebsiella spp. CLH showed higher MDR indices (45.4% with MAR ≥ 0.2) and a higher prevalence of resistance genes, including blaCTX-M-1, blaCTX-M-2, blaCTX-M-8, and blaCMY-2. In FRH, MDR was less frequent (18% with MAR ≥ 0.2), but resistance genes were also detected. In Caatinga biome conditions, CLH demonstrated higher frequency of carrying resistant bacteria, reflecting the intensive management of commercial poultry farming. However, FRH, through contact with the environment and other animals, also represent potential reservoirs of MDR Enterobacterales and associated genes.

Antimicrobial resistance (AMR) is a significant health problem, especially in low- and middle-income countries. This study aimed to investigate the prevalence and trends of antimicrobial resistance (AMR) and multidrug resistance (MDR) in bacterial infections at a tertiary-care hospital in Dhaka, Bangladesh, and the prevalent pathogens and their resistance profiles. A cross-sectional study was conducted on clinical specimens from patients admitted to tertiary-care hospitals, processed at Ibn Sina Diagnostic and Imaging Center in Dhaka, Bangladesh. A total of 3,996 clinical specimens were sampled by patients, with inclusion and exclusion criteria. The samples were blood, urine and wound swabs. Data regarding culture positivity, pathogen distribution and antimicrobial susceptibility were summarized using descriptive statistics. Out of the 3,996 specimens, 72.5% were positive in terms of significant bacterial growth. The gram-negative bacteria were the dominant ones, with Escherichia coli (25.4%) and Klebsiella spp. (20.4%). The most common pathogens are Pseudomonas aeruginosa (15.8%), Acinetobacter spp. (11.9%), Staphylococcus aureus (10%), and Coagulase-negative Staphylococci (8.1%) were the most common gram-positive. In E. coli, the resistance was significantly high with a 42.5% ciprofloxacin resistance and a 47.0% ceftriaxone resistance. MDR was identified in 53.0% of E. coli isolates, and similar MDR patterns were observed in Klebsiella spp. and Pseudomonas aeruginosa. The study shows that there is high-AMR, especially amongst gram-negative pathogens, at a tertiary-care hospital. There is an urgent need to enhance antibiotic stewardship and infection control to deal with the increasing rate of MDR bacterial infections.

Microbial Safety and Antimicrobial Resistance Patterns of Popular Street Foods in Gopalganj, Bangladesh.

Determination of Fosfomycin MIC values in multidrug-resistant Klebsiella pneumoniae isolates and a cost-effective method attempt for routine laboratory testing.

Genomic characterization, antimicrobial resistance and virulence profiles of Klebsiella pneumoniae isolated from mink in Northern China.

Background: Copper oxide nanoparticles (CuO NPs) have attracted increasing attention for their versatile applications in catalysis, biosensing, anticancer therapy, and other biomedical fields. Green synthesis using microbial extracellular components offers a sustainable and eco-friendly alternative to conventional chemical methods. Objective: This study aimed to elucidate the biosynthetic process of copper oxide nanoparticles (Cu(NO₃)₂ NPs) utilizing extracellular components from the environmental isolate Lactobacillus plantarum as a natural reducing and stabilizing agent. Methodology: For nanoparticle synthesis, 1 g of copper nitrate was added to 10 mL of extracellular filtrate. The obtained CuO NPs were characterized using Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectroscopy (FTIR), and Field Emission Scanning Electron Microscopy (FE-SEM). Antibiotic resistance profiles of the bacterial isolates and the antibacterial activity of the CuO NPs were assessed. Results: FE-SEM analysis revealed spherical CuO nanoparticles forming nano-cluster aggregates. All isolates exhibited 100 % resistance to cefotaxime and 91 % resistance to ceftriaxone and lincomycin, while resistance to other antibiotics ranged from 18 % to 73 %. Multidrug resistance was observed in all isolates, with at least four antibiotics resisted. The biosynthesized CuO NPs showed strong antibacterial activity, producing inhibition zones of 33 mm against Staphylococcus saprophyticus (150 % concentration) and 19 mm against Burkholderia cepacia (100 % concentration). Conclusion: Lactobacillus plantarum proved effective for the eco-friendly biosynthesis of CuO NPs. Given the high prevalence of antibiotic resistance, these nanoparticles demonstrate promising potential as alternative antimicrobial agents against multidrug-resistant pathogens.

Background: K. pneumoniae is an opportunistic emerging pathogen responsible for severe hospital-acquired as well as community-acquired infections, often with multidrug resistance and multiple virulence factors, posing a significant clinical challenge due to its ability to cause hard-to-treat infections. Aims: The objective of this study was to identify the phenotypic virulence factors, antibiotic resistance, and molecular identification of dominant virulence genes among K. pneumoniae isolates. Methodology: Twenty clinical isolates were screened. Phenotypic screening included capsule production, biofilm formation, proteinase, gelatinase, hemolysin, and hyaluronidase. Antibiotic susceptibility testing was conducted to determine resistance profiles. Molecular detection targeted virulence genes such as mrkD, T1 fim, magA, and T1fim. Results: Capsule production was detected in 100% isolates, biofilm formation in 75%, proteinase in 80%, gelatinase in 55%, hemolysin in 10%, and hyaluronidase in 15%. Antibiotic susceptibility testing showed high resistance to penicillin (100%), ampicillin (95%), and cephalosporins, while carbapenems demonstrated high effectiveness (imipenem 85% sensitive, meropenem 90% sensitive). Molecular analysis revealed mrkD in 100%, T1 fim in 90%, magA in 65% of isolates, The coexistence of strong virulence determinants and multidrug resistance in K. pneumoniae highlights its elevated pathogenic potential. Conclusion: Molecular characterization of virulence genes provides essential insights for clinical management, therapeutic planning, and infection control strategies.

Overcoming multidrug resistance through fucoidan from molecular mechanisms to nanomedicine applications.

Identifying multidrug-resistant (MDR) bacteria in veterinary hospitals is crucial for treatment and public health risk mitigation. This study assessed the hospital prevalence of MDR isolates from canine bacterial skin infections, compared prevalence across services and infection types, and identified the most common MDR organisms. Data from hospital records and aerobic skin cultures from August 2021 to November 2024 were reviewed and analyzed. The dataset included 438 cultures from 416 patients and 647 bacterial isolates, and 196 MDR bacteria yielded from 182 samples. The hospital multidrug resistance prevalence was 42% among cultures and 30% among bacterial isolates. The highest multidrug resistance prevalence by service included Primary Care with 68%, Neurology with 62%, Dermatology with 49%, and Surgery with 44%. The MDR bacteria prevalence for superficial surgical site infections was 34%, pyodermas 33%, wounds 30%, masses 28%, and abscesses 13%. Dermatology cultured 72 of 196 (37%) MDR bacteria, Surgery 48 (24%), Emergency and Critical Care 27 (14%), Urgent Care 18 (9%), Primary Care 14 (7%), Neurology eight (4%), Internal Medicine six (3%), and Oncology three (2%). Staphylococcus pseudintermedius was the most common MDR bacteria. These results underscore the need for ongoing surveillance, antimicrobial stewardship, and targeted infection control strategies specific to each veterinary setting.

Bovine mastitis remains a major global threat to dairy production and animal welfare, with the increasing emergence of multidrug-resistant (MDR) pathogens severely undermining the efficacy of conventional antimicrobial therapies and complicating disease control strategies. Enterococcus avium, traditionally understudied in livestock, has been occasionally associated with mastitis and poses potential zoonotic and antimicrobial resistance (AMR) risks. This study aimed to investigate the prevalence, AMR, virulence repertoire and genomic features of E. avium isolates from milk, faeces and soil in some selected dairy farms with mastitis in Bangladesh. A total of 110 samples (milk, faecal and soil) were collected and screened for E. avium using selective culture and polymerase chain reaction (PCR). Antimicrobial susceptibility was determined against 15 antibiotics. Four MDR E. avium isolates (4M1, 4S1, 4F1 and 4F2) were selected for whole-genome sequencing (WGS) to characterize their genomic diversity, functional potential, resistome and virulome in dairy cows and associated environments. E. avium was detected in 56.36% of samples, with highest prevalence in milk (47.8%). MDR was highly prevalent (93.5%), with frequent resistance to sulphonamides, nitrofurantoin and oxacillin, whereas gentamicin retained activity. Genomic analyses revealed conserved core genomes alongside variable accessory elements, indicating both evolutionary stability and adaptive potential. Phylogenetic proximity to human-derived strains highlights zoonotic risk. Functional profiling demonstrated robust metabolism, environmental sensing, adhesion-related virulence factors and multiple bacteriocin clusters, supporting persistence and microbial competition. ARGs conferring multidrug efflux, β-lactam and fluoroquinolone resistance were conserved across isolates. E. avium is a prevalent mastitis pathogen, highly conserved among the studied isolates, with significant virulence and AMR profiles, highlighting its zoonotic potential and need for One Health-based surveillance strategies.

Discovery of an N,N'-diarylurea with potent activity against multidrug-resistant Staphylococcus aureus via perturbation of membrane homeostasis.

Attenuation of ABCG2-dependent drug efflux by befotertinib restores chemosensitivity in multidrug-resistant non-small cell lung cancer cells.

Multidrug resistance (MDR) is a major determinant of relapse-associated mortality in pediatric acute lymphoblastic leukemia (pALL). Although miR-326 downregulation has been associated with poor prognosis, its role in chemoresistance remains undefined. This study investigated the mechanistic contribution of miR-326 to MDR in pALL. miR-326 expression was quantified by RT-qPCR in 58 fresh bone marrow samples and 14 paired diagnosis-relapse slides from pALL patients. A multidrug-resistant CD10-CD34- B-cell acute lymphoblastic leukemia (B-ALL) cell line was transfected with miR-326 mimic, and drug sensitivity was assessed by MTT assay. Bioinformatic analyses identified ABCA2 and YY1 as potential targets of miR-326, which were validated by RT-qPCR, Western blotting, and dual-luciferase reporter assays. Low miR-326 expression was associated with relapse and reduced 4-year disease-free survival. Restoration of miR-326 expression enhanced chemosensitivity and downregulated ABCA2 and YY1 at both mRNA and protein levels. Reporter assays confirmed direct targeting of both genes. miR-326 attenuates MDR in pALL through direct suppression of ABCA2 and YY1, highlighting its potential as a therapeutic target for overcoming chemoresistance in pediatric B-ALL.

Multidrug-resistant (MDR) bacterial infections demand antibacterial strategies that circumvent conventional resistance pathways and enable localized action with minimal host toxicity. Photodynamic therapy (PDT) represents a non-invasive approach; however, its effectiveness is constrained by insufficient bacterial targeting, aggregation-caused quenching, and limited reactive oxygen species (ROS) generation under physiological conditions. Herein, we develop two membrane-anchoring naphthalimide-based aggregation-induced emission (AIE) photosensitizers, TPAPV-NIM-mPy-M and TPAPV-NIM-Py-M, engineered via a donor-π-acceptor molecular design to integrate near-infrared (NIR) fluorescence imaging and antibacterial PDT. Both photosensitizers display visible-light absorption, pronounced AIE characteristics, and NIR emission, providing bright signals upon aggregation and facilitating rapid bacterial visualization. Under low-intensity white-light irradiation, they efficiently generate ROS via both type I and type II pathways, supporting oxygen-dependent and partially oxygen-tolerant mechanisms. The introduction of cationic pyridinium units promotes rapid bacterial binding and membrane-specific localization in Gram-positive and Gram-negative bacteria, thereby confining ROS at the bacterial envelope and enhancing photoinactivation. Notably, TPAPV-NIM-Py-M, benefiting from extended π-conjugation and stronger intramolecular charge transfer, exhibits higher ROS output and superior antibacterial efficacy against Escherichia coli (E. coli), Staphylococcus aureus (S. aureus), vancomycin-resistant Enterococcus faecium (VR E. faecium), and multidrug-resistant Escherichia coli (MDR E. coli), while maintaining negligible dark toxicity. Cytotoxicity and hemolysis assays confirm a favorable biocompatibility profile. TPAPV-NIM-Py-M also shows strong antibiofilm activity. Furthermore, TPAPV-NIM-Py-M enables effective in vivo photodynamic elimination of bacteria in an E. coli-infected wound model, significantly accelerating wound closure and tissue regeneration without systemic toxicity. This work establishes a membrane-targeted molecular engineering strategy for high-performance AIE photosensitizers and highlights their potential for image-guided photodynamic treatment of MDR bacterial infections and infected wounds. STATEMENT OF SIGNIFICANCE: Antibiotic resistance and biofilm-associated infections are driving demand for non-antibiotic antibacterial therapies. This study introduces naphthalimide-based aggregation-induced emission photosensitizers that anchor to bacterial membranes, enabling near-infrared fluorescence imaging and localized generation of reactive oxygen species for photodynamic killing. Membrane targeting improves efficacy against both Gram-positive and Gram-negative pathogens, including multidrug-resistant strains, and supports treatment of infected wounds in vivo with good biocompatibility. The work provides a general molecular design strategy for image-guided antimicrobial photodynamic therapy.

Background: Multidrug efflux pumps significantly contribute to bacterial resistance to antimicrobial drugs. The oqxAB efflux pump gene in Klebsiella pneumoniae has been well studied due to its significant contribution to antibiotic resistance. Objectives: This study investigated how Ciprofloxacin at a sub-Minimum Inhibitory Concentration (sub-MIC) affected the expression of the oqxAB efflux pump gene in an isolate of Klebsiella pneumoniae that was MDR (Multidrug-Resistant) with strong biofilm-forming ability. Methodology: Clinical samples were collected from blood, wounds, respiratory infections, and urine for isolation of K. pneumoniae. The isolates were tested for antibiotic susceptibility. Then, the MDR with strong biofilm-forming ability K. pneumoniae isolate were selected and incubated with sub-MIC of ciprofloxacin at early, mid, and late stages of the logarithmic growth phase. The levels of expression of the oqxAB efflux pump genes were then quantified by RT-qPCR. Results: Thirty K. pneumoniae isolates were identified from clinical specimens and tested for antibiotic susceptibility. Exposure of multidrug-resistant, strong biofilm-forming isolate to a sub-MIC of Ciprofloxacin resulted in marked downregulation of efflux pump genes. OqxA expression decreased by 0.3-fold, 0.09-fold, and 0.0001-fold at the early, mid, and late logarithmic phases, respectively, while OqxB expression decreased by 0.08-fold, 0.05-fold, and 0.004-fold at the corresponding stages. Conclusion: The results highlight the significant impact of ciprofloxacin stress in suppressing the expression of the oqxAB efflux pump genes.

Phenotypic and genomic characterization of two novel lytic bacteriophages targeting multidrug-resistant Pseudomonas aeruginosa.