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29 pages, 3610 KB  
Article
Biological Properties of Eucalyptus globulus Oil and Eucalyptol, Chemical Composition and Molecular Docking
by Ilyass Lkhalidi, Aimad Allali, Hamza Saghrouchni, Mohamed Chebaibi, Rachid Flouchi, Ibrahim Mssillou, Ana Tomić, Asaad Khalid, Abdelkrim Agour, Youness El Abdali, Issam Ghabbour and Moulay Larbi Ouahidi
Biophysica 2026, 6(5), 88; https://doi.org/10.3390/biophysica6050088 - 11 Sep 2026
Abstract
Background: Moroccans employ Eucalyptus globulus Labill., a medicinal herb, to cure a variety of ailments. This research aimed to evaluate the chemical constituents of Eucalyptus globulus essential oil (EGEO) to determine their composition and potential use as hemolytic, antioxidant, and antimicrobial agents. Methods: [...] Read more.
Background: Moroccans employ Eucalyptus globulus Labill., a medicinal herb, to cure a variety of ailments. This research aimed to evaluate the chemical constituents of Eucalyptus globulus essential oil (EGEO) to determine their composition and potential use as hemolytic, antioxidant, and antimicrobial agents. Methods: GC analysis was utilized to determine the composition of EGEO harvested in the province of Meknes. Using the disk diffusion technique, MIC, MBC, and MFC tests, antibacterial and antifungal activity were assessed against pathogenic microorganisms. DPPH, TAC, and FRAP experiments were used to evaluate the antioxidant potential of EGEO and Eucalyptol. The main chemical binding affinities were predicted by Molecular Docking analysis. GraphPad Prism (v8) was used to evaluate these findings using a Tukey and ANOVA analysis. Results: GC-MS revealed 27 components, including Eucalyptol (1,8-Cineole) (55.07%). Hemolysis recorded the greatest value, 8.16 ± 0.13. Staphylococcus aureus had the highest MIC values (1.25 mg/mL). Bacillus subtilis had a 65 mm inhibitory zone. The fungicidal effectiveness of EGEO and its major component varies according to the studied fungus strain. In terms of antioxidant characteristics, DPPH radical inhibition revealed that 1,8-Cineole has a higher IC50 (4.7 ± 0.5 µg/mL). The Total Antioxidant Capacity was 22 ± 0.02 mg AAE/g. FRAP analysis showed that Eucalyptol is more potent than EGEO. Conclusion: Antimicrobial and antioxidant studies support the use of EGEO and eucalyptol in traditional and therapeutic medicine, and show their numerous possible uses as natural preservatives for perfumes and foods, as well as anticancer agents due to their hemolytic capacity. Full article
(This article belongs to the Special Issue Latest Advances in Molecular Docking Involved in Biophysics)
14 pages, 740 KB  
Article
Molecular Characterization of Colistin Resistance Acinetobacter baumannii Isolates and Identification of Mutations in pmrA and lpxA Genes from a Tertiary Care Hospital in South India
by MuthuLakshmi BackiaSubramanian, Madhumala Shanmugasundaram, Shanthi Mariappan, Uma Sekar, Renuka M K and Thyagarajan Ravinder
Antibiotics 2026, 15(9), 846; https://doi.org/10.3390/antibiotics15090846 - 31 Aug 2026
Viewed by 222
Abstract
Background/Objectives: Acinetobacter baumannii is a multidrug-resistant (MDR) nosocomial pathogen associated with significant morbidity and mortality. The emergence of strains resistant to multiple antibiotics has markedly reduced available treatment options. A. baumannii now demonstrates resistance to most first-line antibiotics, resulting in the extensive [...] Read more.
Background/Objectives: Acinetobacter baumannii is a multidrug-resistant (MDR) nosocomial pathogen associated with significant morbidity and mortality. The emergence of strains resistant to multiple antibiotics has markedly reduced available treatment options. A. baumannii now demonstrates resistance to most first-line antibiotics, resulting in the extensive use of colistin, which in turn has led to the emergence of colistin-resistant strains. There are very limited studies from India on the mechanisms of colistin resistance. In this study, we focused on the molecular mechanisms leading to colistin resistance. Methods: A total of 225 clinical isolates of Acinetobacter baumannii were analyzed in this study. Antimicrobial susceptibility testing was done using the disk diffusion method for various classes of antimicrobial agents as per the Clinical Laboratory Standards Institute (CLSI M100 Ed 35,2025). Susceptibility to colistin was tested by the Microbroth dilution method. Colistin resistance mediated by the mcr gene and alterations in the pmrAB and lpxACD genes were investigated using conventional PCR followed by mutational analysis. Results: Among the 225 isolates, 4 isolates were found to be colistin resistant. All the resistant isolates had an MIC ≥ 16 mcg/mL. Mutations were found in lpxA and pmrB (c.391T > C, c.495T > C, c.516A > G, c.732A > G and c.966T > C). Mutations in pmrA, lpxC, and lpxD were not detected in this study. Mcr-1 gene was not detected in this study. Conclusions: Colistin is the last resort for the treatment of MDR strains, and the increase in resistance to colistin has become a huge concern among the medical community as it reduces the options available for treatment. This is the first report on the molecular mechanisms of colistin resistance in South India using PCR. The study is also the first to report four novel mutations in the genes that may be responsible for resistance. Early detection of resistance and swift control measures can help curb the morbidity and mortality rate among such A. baumannii strains. Full article
(This article belongs to the Special Issue Antibiotic Resistance Genes: Mechanisms, Evolution and Dissemination)
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22 pages, 11479 KB  
Article
Hybrid Cloud Segmentation Approach Combining YOLOv8 Instance Segmentation with HSV Thresholding for Multi-Site Assessment
by Augustin Alexandru Besu, Enrique García-Campos, Gabriel López, Mauricio Trigo-González and Joaquín Alonso-Montesinos
Remote Sens. 2026, 18(17), 2869; https://doi.org/10.3390/rs18172869 - 24 Aug 2026
Viewed by 230
Abstract
Accurate cloud segmentation from ground-based fisheye camera imagery is essential for solar irradiance forecasting and photovoltaic system optimization. Traditional computer vision approaches, such as HSV thresholding and K-means clustering, face significant limitations when applied globally to sky images due to the spectral similarity [...] Read more.
Accurate cloud segmentation from ground-based fisheye camera imagery is essential for solar irradiance forecasting and photovoltaic system optimization. Traditional computer vision approaches, such as HSV thresholding and K-means clustering, face significant limitations when applied globally to sky images due to the spectral similarity between cloud regions and sky areas under varying atmospheric conditions. This study presents a hybrid methodology that leverages YOLOv8 instance segmentation to provide contextual cloud regions followed by refined HSV thresholding within these detected areas. The approach incorporates solar trajectory modeling using pvlib for accurate sun disk detection and exclusion, preventing false cloud classification. The methodology was developed and validated at the CIESOL using Mobotix Q71 fisheye cameras, and later tested in Antofagasta (Chile) and Huelva (Spain). The YOLOv8l-seg model achieved a mask precision of 0.821 and box mAP@0.5 of 0.680 on validation data. The results show a promising correlation with radiometric measurements such as clearness index kt and diffuse fraction kd in preliminary validation cases. While YOLOv8 demonstrates good cross-site generalization, HSV thresholding requires camera-specific calibration for optimal performance. The method addresses the context-dependency limitations of traditional algorithms, though computational performance and broader validation remain areas for future work. Full article
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31 pages, 9789 KB  
Article
Ultrasound-Assisted Hydrodistillation of Essential Oils for Eco-Friendly Biocontrol of Botrytis cinerea in Grapevines
by Florin Nenciu, Ana-Maria Tăbărașu, Cristina Fătu, Nicolae-Valentin Vlăduț, Iulian Voicea and Sorina Dinu
Horticulturae 2026, 12(9), 1054; https://doi.org/10.3390/horticulturae12091054 - 23 Aug 2026
Cited by 1 | Viewed by 346
Abstract
Botrytis cinerea is a major fungal pathogen of grapevine responsible for gray mold, causing significant economic losses worldwide. Under specific environmental conditions, controlled development of Botrytis cinerea may lead to “noble rot,” a quality-enhancing attribute of premium wines; however, the same fungus can [...] Read more.
Botrytis cinerea is a major fungal pathogen of grapevine responsible for gray mold, causing significant economic losses worldwide. Under specific environmental conditions, controlled development of Botrytis cinerea may lead to “noble rot,” a quality-enhancing attribute of premium wines; however, the same fungus can rapidly develop into destructive gray mold, causing significant grape losses. Consequently, the challenge is not necessarily the complete eradication of the pathogen, but the regulation of its development to prevent uncontrolled disease progression while preserving grape quality. The present study investigated the potential of using essential oils extracted from selected aromatic plants using ultrasound-assisted hydrodistillation (UAHD) as eco-friendly biocontrol agents against Botrytis cinerea. The extraction process was optimized by evaluating the effects of biomass particle size, ultrasonic power, and distillation time on essential oil yield. Antifungal activity was assessed through in vitro poisoned food and disk diffusion assays and validated in vivo on artificially inoculated grape berries by evaluating disease incidence, disease severity, treatment efficacy, and weight loss. Ultrasound pretreatment increased essential oil yield by up to 29.58% compared with conventional hydrodistillation, with optimal conditions achieved using 1 cm biomass, 150 W ultrasonic power, and 85 min distillation. Oregano, thyme, sage, and lemon balm essential oils achieved 100% inhibition of Botrytis cinerea mycelial growth at the tested concentrations, whereas lavender essential oil showed 95.03% inhibition at 0.125% and complete inhibition at 0.25%. In vivo, essential oil formulations markedly reduced gray mold development, with the 2.0% formulation providing the highest treatment efficacy and the lowest disease severity. These findings show that UAHD-derived essential oils represent promising sustainable alternatives for the management of Botrytis cinerea in viticulture. However, these findings represent preliminary evidence obtained under controlled in vitro conditions, necessitating further validation in real-world applications. Full article
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12 pages, 285 KB  
Article
Prevalence, Serotype Distribution, and Antimicrobial Resistance of Streptococcus agalactiae Among Pregnant Women in Greece: A Retrospective Study
by Anthia Chasiakou, George Kaparos, Stamatia Chasiakou, Stiliani Demeridou, Vasiliki Koumaki and Athanasios Tsakris
J. Clin. Med. 2026, 15(16), 6458; https://doi.org/10.3390/jcm15166458 - 20 Aug 2026
Viewed by 305
Abstract
Background: Streptococcus agalactiae (group B Streptococcus, GBS) remains a leading cause of invasive infections in pregnant women, fetuses, and neonates. Universal screening at 36–37 weeks of gestation and intrapartum antimicrobial prophylaxis are essential to prevent adverse outcomes. This study aimed to [...] Read more.
Background: Streptococcus agalactiae (group B Streptococcus, GBS) remains a leading cause of invasive infections in pregnant women, fetuses, and neonates. Universal screening at 36–37 weeks of gestation and intrapartum antimicrobial prophylaxis are essential to prevent adverse outcomes. This study aimed to determine the prevalence, serotype distribution, and antimicrobial susceptibility of GBS isolates among pregnant women in Greece. Methods: Vaginal and rectal swabs were collected from pregnant women undergoing GBS screening between January 2021 and December 2025. Samples were processed using Todd-Hewitt broth with colistin and nalidixic acid, and cultured on blood agar and chromogenic media. The VITEK2 system was used for GBS identification and antimicrobial susceptibility testing against penicillin, erythromycin, clindamycin, tetracycline, levofloxacin, and vancomycin, according to EUCAST guidelines. The double-disk diffusion test was used for macrolide-lincosamide-streptogramin B (MLSB) phenotyping. Serotyping for all ten serotypes was conducted using a commercial latex agglutination assay. Results: Among 941 women screened, 118 (12.5%) were colonized with GBS. The most prevalent serotypes were III (29.7%), V (18.6%), Ib (14.4%), IX (10.2%), Ia (9.3%), and II (9.3%). All isolates were susceptible to penicillin. Resistance to erythromycin and/or clindamycin was detected in 37 isolates. In these isolates, the predominant MLSB phenotype was constitutive (cMLSB, 78.4%), followed by inducible (iMLSB, 13.5%), L (5.4%), and M (2.7%) phenotypes. Conclusions: GBS colonization was detected in 12.5% of pregnant women, with serotype III predominating, underscoring its clinical relevance due to its association with invasive neonatal disease. Although penicillin remains fully effective, the observed resistance to macrolides and lincosamides, primarily mediated by the cMLSB phenotype, raises concerns regarding alternative therapies. Full article
(This article belongs to the Section Infectious Diseases)
12 pages, 1946 KB  
Article
Fluconazole Disk Diffusion on CHROMagar Candida Plus for Differentiation Between Candidozyma auris and Candida parapsilosis
by Sarah Israel, Jonathan Lellouche, Loujin Ardda, Ariel Israel, Sharon Amit, Ronen Ben-Ami, Itzhack Polacheck, Jacob Moran-Gilad and Maya Korem
J. Fungi 2026, 12(8), 606; https://doi.org/10.3390/jof12080606 - 13 Aug 2026
Viewed by 437
Abstract
Background: This study evaluated the utility of fluconazole disk diffusion on CHROMagar Candida Plus for differentiating Candidozyma auris from Candida parapsilosis. Methods: In this in vitro study, clinical isolates of both C. auris and C. parapsilosis were used. Antifungal susceptibility testing was [...] Read more.
Background: This study evaluated the utility of fluconazole disk diffusion on CHROMagar Candida Plus for differentiating Candidozyma auris from Candida parapsilosis. Methods: In this in vitro study, clinical isolates of both C. auris and C. parapsilosis were used. Antifungal susceptibility testing was performed via broth microdilution and disk diffusion with different fluconazole concentrations on both CHROMagar Candida Plus and RPMI agar. Colony color was also assessed. Results: This study demonstrates high categorical agreement between disk diffusion on CHROMagar Candida Plus and broth microdilution for both species. An optimal cut-off zone diameter of 10 mm was identified on CHROMagar Candida Plus with 50 µg fluconazole, providing 91% sensitivity and 90% specificity for differentiating the two species. Notably, at 24 h, 83 out of 88 (94.3%) C. auris isolates exhibited a bluish, blue-green, or turquoise coloration on the reverse side of the plate, suggesting that reverse-side colony color on CHROMagar may serve as a supportive phenotypic indicator when combined with disk diffusion testing, to differentiate C. auris from C. parapsilosis in the laboratory setting. Conclusions: Fluconazole disk diffusion on CHROMagar Candida Plus, supplemented by reverse-side colony coloration, offers a practical, low-cost adjunctive strategy to aid in the differentiation of C. auris and C. parapsilosis in clinical laboratories. Full article
(This article belongs to the Section Fungal Pathogenesis and Disease Control)
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14 pages, 2135 KB  
Article
Associations of Biofilm Capacity with Antimicrobial Resistance and Virulence Genes in Klebsiella pneumoniae from Chickens in Henan, China, 2023–2025
by Han Zhang, Jiayi Li, Shiqi Deng, Jiani Lei, Liping Gao, Xiangyang Li, Lili Gao, Yuyang Yuan, Hua Wu, Yajun Zhai and Jianhua Liu
Antibiotics 2026, 15(8), 767; https://doi.org/10.3390/antibiotics15080767 - 10 Aug 2026
Viewed by 310
Abstract
Background: Klebsiella pneumoniae is an opportunistic zoonotic pathogen that can cause respiratory diseases in chickens. The aim of this study was to investigate the biofilm formation, resistance, and virulence of K. pneumoniae isolates from chickens in Henan Province, China, between 2023 and [...] Read more.
Background: Klebsiella pneumoniae is an opportunistic zoonotic pathogen that can cause respiratory diseases in chickens. The aim of this study was to investigate the biofilm formation, resistance, and virulence of K. pneumoniae isolates from chickens in Henan Province, China, between 2023 and 2025, and to analyze the associations among these characteristics. Methods: We identified the isolates through blood agar culture, Gram staining and matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Hypermucoviscosity phenotype, biofilm-forming ability, antimicrobial resistance and virulence genes were assessed by the string test, crystal violet assay, disk diffusion and polymerase chain reaction (PCR), respectively. Results: A total of 102 K. pneumoniae isolates were identified. Of these, 81.4% were biofilm-forming strains, and 15.7% exhibited the hypermucoviscosity phenotype. The susceptibility profiles of the K. pneumoniae isolates indicated high resistance to penicillins (>90.0%) and low resistance to carbapenems (<10%), with 88.2% identified as multidrug-resistant. The results of virulence gene detection indicated that luxS (79.4%), mrkD (75.5%), and uge (73.5%) were the most prevalent virulence genes, followed by wabG (49.0%), ybtA (34.3%), and iucA (20.6%). The association analysis indicated that biofilm formation was significant association with multidrug-resistant and the carriage of virulence genes. Compared with non–biofilm–forming isolates, biofilm–forming isolates showed significantly higher resistance to ceftiofur and florfenicol, as well as higher detection rates of luxS, mrkD, and uge (p < 0.05). Conclusions: The data obtained in this study reveal the pathogenic potential and multidrug–resistant characteristics of this pathogen, highlighting the need for surveillance and monitoring. Full article
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11 pages, 1357 KB  
Article
Diverse Genomic Mechanisms of cfiA Activation in Carbapenem-Resistant Bacteroides fragilis Clinical Isolates from Korea
by Yangsoon Lee, Hyukmin Lee, Yoon Soo Park, Myungsook Kim and Kyungwon Lee
Antibiotics 2026, 15(8), 763; https://doi.org/10.3390/antibiotics15080763 - 9 Aug 2026
Viewed by 320
Abstract
Background: Bacteroides fragilis is the most clinically important anaerobic bacterium and has shown increasing carbapenem resistance mediated by the cfiA metallo-β-lactamase. Although insertion sequence (IS)-mediated activation of cfiA is a well-recognized mechanism, the contribution of IS-independent genomic mechanisms remains incompletely characterized. This [...] Read more.
Background: Bacteroides fragilis is the most clinically important anaerobic bacterium and has shown increasing carbapenem resistance mediated by the cfiA metallo-β-lactamase. Although insertion sequence (IS)-mediated activation of cfiA is a well-recognized mechanism, the contribution of IS-independent genomic mechanisms remains incompletely characterized. This study investigated the phenotypic and genomic mechanisms of cfiA-associated carbapenem resistance in clinical B. fragilis isolates from Korea. Methods: Twenty-six non-duplicate carbapenem-nonsusceptible B. fragilis isolates were collected from three Korean institutions between 2022 and 2023. Antimicrobial susceptibility was tested by disk diffusion and agar dilution methods, and carbapenemase activity was assessed using the anaerobic carbapenem inactivation method (Ana-CIM) and the meropenem double-ended Etest. Whole-genome sequencing was performed to identify resistance determinants, insertion sequences, promoter structures, and multilocus sequence types. Results: Among 26 isolates, 12 (46.2%) were cfiA-positive and 14 (53.8%) were cfiA-negative. High-level resistance (imipenem MIC ≥ 32 mg/L; meropenem MIC ≥ 128 mg/L) was observed in four cfiA-positive isolates carrying activating IS elements (IS1187 or IS942) upstream of cfiA. Notably, three additional highly resistant cfiA-positive isolates lacked upstream IS elements and showed distinct genomic features, including tandem duplication of cfiA2 (SEV23_101), duplicated promoter architecture upstream of cfiA14 (SEV23_15), and high-level resistance associated with cfiA18 (SCL22_40). Ana-CIM yielded positive results only among isolates with meropenem MIC ≥ 128 mg/L, whereas the meropenem double-ended Etest failed to discriminate cfiA-associated carbapenemase activity. Conclusions: These findings indicate that high-level carbapenem resistance in B. fragilis may be associated with several genomic features, including IS-mediated activation, increased cfiA gene dosage, and promoter amplification. Molecular characterization is therefore essential for accurate interpretation of carbapenem resistance in B. fragilis. Full article
(This article belongs to the Section Mechanism and Evolution of Antibiotic Resistance)
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20 pages, 869 KB  
Article
Physicochemical and Microbiological Properties of Yoghurt Made Form Defatted Milk Mixtures and Concentrated Buttermilk Fortified with Herbal Extract
by Tamara Tultabayeva, Gulmira Zhakupova, Assem Sagandyk, Kadyrzhan Makangali, Alfiya Syzdykova, Aisarat Gajimuradova, Aknur Muldasheva and Kalamkas Dairova
Foods 2026, 15(16), 2768; https://doi.org/10.3390/foods15162768 - 7 Aug 2026
Viewed by 391
Abstract
This study evaluates the impact of plant-derived additives (Melissa officinalis L., Plantago major L., and Inula helenium L.) on the physicochemical, microbiological, and antimicrobial properties of yoghurt formulated with a combined base of milk and buttermilk concentrate (solid content 8–10%). Over 14 [...] Read more.
This study evaluates the impact of plant-derived additives (Melissa officinalis L., Plantago major L., and Inula helenium L.) on the physicochemical, microbiological, and antimicrobial properties of yoghurt formulated with a combined base of milk and buttermilk concentrate (solid content 8–10%). Over 14 days of refrigerated storage, all fortified yoghurts maintained pH within acceptable limits, while Plantago and Inula slightly enhanced post-acidification without compromising quality. Notably, the buttermilk concentrate significantly boosted initial lactic acid bacteria (LAB) viability, and the yoghurt with Plantago major L. extract showed a 314% higher viable LAB count during storage compared with the control. In contrast, Inula helenium L. reduced LAB viability by 67.6%, indicating a trade-off between bioactivity and starter compatibility. Antimicrobial testing via disk-diffusion revealed selective activity against Gram-positive Staphylococcus aureus (maximum inhibition radius: 5.8 ± 0.5 mm for Plantago yoghurt), with no effect on Gram-negative E. coli or P. aeruginosa. Activity was driven primarily by acid-dependent metabolites, with Plantago retaining residual non-acidic bioactivity after neutralization. The combination of Plantago major L. with buttermilk concentrate emerged as optimal for functional yoghurt, enhancing higher viability of lactic acid bacteria during refrigerated storage. These findings support the use of compatible plant–dairy combinations to develop yoghurt products with improved physicochemical properties, LAB viability and microbiological stability under the tested conditions. Full article
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18 pages, 10167 KB  
Article
Dielectrophoretic Enrichment Coupled with Impedance Spectroscopy for Real-Time Bacterial Detection and Antibiotic Susceptibility Testing Using an Interdigitated Wave Electrode Array
by Zeeshan and Naeem Iqbal
Sensors 2026, 26(15), 4984; https://doi.org/10.3390/s26154984 - 6 Aug 2026
Viewed by 322
Abstract
Antimicrobial resistance (AMR), largely driven by the inappropriate and excessive use of antibiotics, requires rapid and reliable bacterial detection and antibiotic susceptibility testing (AST), as conventional culture-based methods remain time-intensive. Here, we report a real-time, label-free interdigitated wave electrode array (IWEA) that combines [...] Read more.
Antimicrobial resistance (AMR), largely driven by the inappropriate and excessive use of antibiotics, requires rapid and reliable bacterial detection and antibiotic susceptibility testing (AST), as conventional culture-based methods remain time-intensive. Here, we report a real-time, label-free interdigitated wave electrode array (IWEA) that combines dielectrophoretic (DEP) enrichment with impedance spectroscopy for rapid bacterial detection and AST. The proposed IWEA was designed and optimized via COMSOL Multiphysics to enhance DEP-relevant electric-field strength, thereby improving DEP-assisted bacterial enrichment compared to conventional planar interdigitated electrodes. The platform enabled sensitive detection of both Gram-positive (Staphylococcus aureus) and Gram-negative (Escherichia coli) in 0.1× PBS across 10–105 CFU/mL within 30 min using DEP-assisted preconcentration (100 kHz, 10 Vpp), outperforming passive (non-DEP) operation (102–105 CFU/mL). For AST, bacterial responses to vancomycin, gentamicin, and ampicillin were monitored through impedance variations following DEP-based enrichment. Susceptible bacteria produced concentration-dependent reductions in ΔZ/Z0, whereas resistant bacteria showed similar responses to untreated controls. Quantitative assessment yielded CC50 values of 2.86 ± 0.22 µg/mL and 3.06 ± 0.20 µg/mL for vancomycin and gentamicin against S. aureus, and 4.59 ± 0.30 µg/mL for gentamicin against E. coli. Resistance profiles of S. aureus to ampicillin and E. coli to vancomycin and ampicillin were clearly distinguished. SEM imaging and disk diffusion assays independently validated the impedance-derived susceptibility results. Collectively, this IWEA platform offers a rapid, label-free, and quantitative approach for bacterial detection and AST, with strong potential for antimicrobial screening and point-of-care diagnostics. Full article
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17 pages, 791 KB  
Article
Baseline Investigation of Non-Wild-Type Bacterial Indicators and Antibiotic Resistance Genes in Urban Wastewater from Patras, Greece
by Zoi Anastopoulou, Konstantina Charalambous, Angelos Padouvas, Rafail Fokas, Kalypso-Angeliki Koukouvini, Maria Athanasiou, Nikolaos Giormezis, Despoina Gkentzi and Apostolos Vantarakis
Microorganisms 2026, 14(8), 1714; https://doi.org/10.3390/microorganisms14081714 - 4 Aug 2026
Viewed by 301
Abstract
Antimicrobial resistance (AMR) is a major public health concern, and wastewater monitoring can complement clinical surveillance by capturing resistance signals at the population level. This exploratory study assessed selected antibiotic-resistant bacteria and antimicrobial resistance genes (ARGs) in untreated influent wastewater from the municipal [...] Read more.
Antimicrobial resistance (AMR) is a major public health concern, and wastewater monitoring can complement clinical surveillance by capturing resistance signals at the population level. This exploratory study assessed selected antibiotic-resistant bacteria and antimicrobial resistance genes (ARGs) in untreated influent wastewater from the municipal wastewater treatment plant of Patras, Greece. Escherichia coli, Pseudomonas aeruginosa, and Enterococcus spp. were isolated using culture-based methods, tested for antimicrobial susceptibility by disk diffusion and Etest according to EUCAST epidemiological cut-off values, and screened by real-time PCR for intI1, sul1, qnrS1, blaTEM, blaVIM, vanA, and ermB. Among 16 E. coli isolates, non-wild-type (non-WT) profiles were detected on 14/16 for meropenem and 15/16 for ciprofloxacin, whereas only 1/16 was non-WT for ampicillin. All 13 P. aeruginosa isolates were wild type (WT) for meropenem but non-WT for ciprofloxacin, while all 17 Enterococcus spp. isolates were WT for vancomycin and ampicillin. Molecular screening showed that blaTEM was the most frequently detected gene in E. coli, while intI1 and sul1 were detected in subsets of P. aeruginosa isolates. No targeted ARGs were detected in Enterococcus spp. These findings provide preliminary, site-specific baseline information on selected AMR phenotypes and genetic determinants in wastewater-derived bacterial isolates from Patras. Full article
(This article belongs to the Special Issue Epidemiology of Foodborne and Waterborne Diseases)
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25 pages, 26001 KB  
Article
Intestinal Microecology Dysbiosis, Cultivable Pathogen Composition, and Antimicrobial Susceptibility Profiles Associated with Intestinal Exposure and Ocular Opacity in Hybrid Porcupinefish
by Xiaojie Bai, Zuoping Xie, Xiangyu Du, Fangyan Jiang, Ning Yang and Hai Huang
Microorganisms 2026, 14(8), 1703; https://doi.org/10.3390/microorganisms14081703 - 3 Aug 2026
Viewed by 340
Abstract
Intestinal exposure and ocular opacity occur in cultured hybrid porcupinefish, but the associated pathological lesions and gut microecological changes remain poorly characterized. Hybrid porcupinefish were assigned to a healthy control group (CT-CD-JK), an intestinal exposure group (CT-CD-FB), or an ocular opacity group (CT-YQ-FB). [...] Read more.
Intestinal exposure and ocular opacity occur in cultured hybrid porcupinefish, but the associated pathological lesions and gut microecological changes remain poorly characterized. Hybrid porcupinefish were assigned to a healthy control group (CT-CD-JK), an intestinal exposure group (CT-CD-FB), or an ocular opacity group (CT-YQ-FB). Gut microbiota, histopathology, cultivable bacteria, and antimicrobial susceptibility were assessed using 16S rRNA sequencing, hematoxylin and eosin (H&E) staining, bacterial isolation and identification, and disk diffusion testing. Diseased fish showed evident intestinal and ocular tissue injury. Microbial richness was reduced in the CT-CD-FB group, and gut microbial community structure differed among groups (permutational multivariate analysis of variance [PERMANOVA], R2 = 0.5058, p = 0.001). At the phylum level, Firmicutes increased in the CT-CD-FB group, whereas Proteobacteria accounted for a higher proportion in the CT-CD-JK group. Linear discriminant analysis effect size (LEfSe) further indicated group-specific enrichment patterns. A total of 23 cultivable isolates were obtained, among which isolates assigned as putative Vibrio harveyi based on 16S rRNA sequence alignment accounted for 90.9% of isolates derived from intestinal contents in the CT-CD-FB group, which was higher than the 16.7% observed in the CT-CD-JK group. Antimicrobial susceptibility testing suggested a potential multidrug-resistance risk among the isolates; however, higher proportions of susceptible (S) isolates were observed for ceftriaxone (CTR), quinolones, aminoglycosides, and chloramphenicol (C). These preliminary findings suggest that gut dysbiosis, intestinal tissue injury, and a higher detection proportion of putative Vibrio harveyi were associated with intestinal exposure in this small cohort of naturally diseased hybrid porcupinefish, providing a basis for subsequent pathogen-verification studies and antimicrobial-susceptibility assessment. Full article
(This article belongs to the Section Antimicrobial Agents and Resistance)
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15 pages, 659 KB  
Article
Phytochemical Screening and Antibacterial Activity of Jatropha multifida L. (Coral Bush) Leaf Extract-Based Soap Against Staphylococcus aureus and Escherichia coli
by Trixie Joy B. Gano and Ariel M. Alcones
Cosmetics 2026, 13(4), 193; https://doi.org/10.3390/cosmetics13040193 - 29 Jul 2026
Viewed by 590
Abstract
The development of bio-based hygiene products offers a sustainable approach to managing infectious topical pathogens while reducing dependence on synthetic antimicrobials. This study evaluated the antibacterial efficacy of soap formulated with Jatropha multifida leaf ethanolic extract (25%, 50%, and 75% v/v [...] Read more.
The development of bio-based hygiene products offers a sustainable approach to managing infectious topical pathogens while reducing dependence on synthetic antimicrobials. This study evaluated the antibacterial efficacy of soap formulated with Jatropha multifida leaf ethanolic extract (25%, 50%, and 75% v/v) against Staphylococcus aureus and Escherichia coli. Antibacterial activity was determined using the Kirby–Bauer disk diffusion method alongside positive and negative controls. All extract-infused soap formulations exhibited distinct, measurable zones of inhibition (ZOI) ranging from 16.33 mm to 17.67 mm for S. aureus and 16.33 mm to 18.00 mm for E. coli, consistently achieving an “Active” qualitative classification. A one-way analysis of variance (ANOVA) demonstrated highly significant differences across the entire dataset (p < 0.001). However, Tukey’s Honestly Significant Difference (HSD) post hoc test revealed no statistically significant differences in antibacterial performance among the 25%, 50%, and 75% concentrations (p > 0.05). This indicates a performance plateau caused by agar diffusion limits or micellar entrapment within the soap base. J. multifida maintains antibacterial integrity within a soap matrix, offering a viable plant-based antiseptic alternative against S. aureus and E. coli. Formulating at a 25% concentration represents the optimal commercial choice, maximizing antimicrobial performance while minimizing raw material costs. Full article
(This article belongs to the Section Cosmetic Formulations)
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17 pages, 1522 KB  
Article
Phenotypic Antimicrobial Resistance in Escherichia coli and Salmonella spp. Recovered from Broiler-Farm Environmental Matrices in Morocco
by Walid Atiki, Najia Ameur, Atika Zidouh, Abdelmoula Elouardi and Latifa Tahri
Antibiotics 2026, 15(8), 731; https://doi.org/10.3390/antibiotics15080731 - 28 Jul 2026
Viewed by 381
Abstract
Background/Objectives: Antimicrobial resistance (AMR) in poultry-production environments is an important One Health concern. This phenotypic baseline study investigated the detection and antimicrobial-resistance profiles of Escherichia coli and Salmonella spp. recovered from broiler-farm environmental matrices in the Rabat–Salé–Kénitra region of Morocco. Methods: [...] Read more.
Background/Objectives: Antimicrobial resistance (AMR) in poultry-production environments is an important One Health concern. This phenotypic baseline study investigated the detection and antimicrobial-resistance profiles of Escherichia coli and Salmonella spp. recovered from broiler-farm environmental matrices in the Rabat–Salé–Kénitra region of Morocco. Methods: A cross-sectional field study was conducted in 13 broiler farms on 35 sampling dates between 24 November 2023 and 28 April 2025. A total of 543 samples were collected from poultry manure, drinking troughs, farm soil, soils approximately 200 and 500 m from the poultry houses, and well water. Isolates were identified by culture and API 20E; Salmonella spp. identification was additionally confirmed by real-time PCR. Disk-diffusion results were interpreted using applicable CLSI M100, 31st edition, criteria, and colistin was tested by the colistin broth disk elution MIC method. Multidrug resistance (MDR) was defined as resistance to at least one agent in three or more antimicrobial classes. ResultsEscherichia coli and Salmonella spp. were detected in 190/543 (35.0%) and 127/543 (23.4%) samples, respectively. Among E. coli isolates, 115/190 (60.5%) were MDR; the highest matrix-specific proportions occurred in farm soil (85.7%), drinking troughs (83.3%), and poultry manure (75.7%). Among Salmonella spp. isolates, 82/127 (64.6%) were MDR, with the highest proportions in poultry manure (92.9%) and drinking troughs (78.3%). The predominant resistance rates were ampicillin (84.7%), tetracycline (61.6%), and chloramphenicol (55.8%) in E. coli, and nalidixic acid (73.2%), ampicillin (61.4%), and tetracycline (55.9%) in Salmonella spp. Resistant isolates were also detected in surrounding soils and well water; however, the study design did not permit source attribution or inference of transmission direction. Conclusions: Broiler-farm environmental matrices in the study area may represent reservoirs of phenotypically antimicrobial-resistant E. coli and Salmonella spp. The findings provide baseline evidence supporting integrated One Health surveillance, improved biosecurity, manure and litter management, water-system sanitation, and responsible veterinary antimicrobial use. Genomic typing and environmental source-tracking are required to determine persistence and transmission pathways. Full article
(This article belongs to the Special Issue Advances in Antimicrobial Action and Resistance)
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31 pages, 6482 KB  
Article
Continuous Inhibition-Zone Modeling and Binary Classification for Pseudomonas aeruginosa Hit Prioritization: A Retrospective QSAR Evaluation
by Sukrit Kashyap, Barlina Konwar, Ji Young Lee and Kwang-sun Kim
Pharmaceuticals 2026, 19(8), 1173; https://doi.org/10.3390/ph19081173 - 27 Jul 2026
Viewed by 384
Abstract
Background/Objectives: Antibiotic-resistant Pseudomonas aeruginosa and limited experimental validation capacity motivate efficient prioritization of antibacterial candidates from large chemical libraries. Quantitative structure–activity relationship (QSAR) benchmarks often binarize disk diffusion inhibition-zone (IZ) measurements, obscuring activity gradients and imposing threshold dependence. We examined whether continuous-IZ modeling [...] Read more.
Background/Objectives: Antibiotic-resistant Pseudomonas aeruginosa and limited experimental validation capacity motivate efficient prioritization of antibacterial candidates from large chemical libraries. Quantitative structure–activity relationship (QSAR) benchmarks often binarize disk diffusion inhibition-zone (IZ) measurements, obscuring activity gradients and imposing threshold dependence. We examined whether continuous-IZ modeling provides complementary retrospective prioritization relative to calibrated binary classification in a highly imbalanced dataset. Methods: In this retrospective matched-data evaluation, we revisited a published ChEMBL-derived P. aeruginosa disk diffusion dataset using preserved training and locked external validation partitions. A calibrated support vector classifier using Molecular ACCess System keys (SVC/MACCS) provided conservative binary active calls. RegressionStack combined source-descriptor extreme gradient boosting (XGBoost) and ElasticNet regressors, Morgan-fingerprint random forest and gradient-boosting regressors, and a MACCS-key XGBoost regressor through an XGBoost meta-regressor to predict continuous IZ. Results: On the locked external set (n = 1130; 87 actives), SVC/MACCS achieved a positive predictive value (PPV) = 0.619, receiver operating characteristic area under the curve (ROC-AUC) = 0.857, precision–recall area under the curve (PR-AUC) = 0.479, and enrichment factor at 1% (EF@1%) = 7.58. RegressionStack achieved a mean absolute error (MAE) = 3.20 mm, ROC-AUC = 0.896, PR-AUC = 0.545, and EF@1% = 9.74. Neither paired permutation tests (ROC-AUC, p = 0.501; PR-AUC, p = 0.442) nor paired bootstrap confidence intervals resolved these differences. The y-randomization analyses supported non-random signals; scaffold-grouped validation retained early enrichment but showed reduced broader performance. The consensus-positive tier contained 27 actives among 35 nominations (PPV = 0.771). At measured IZ ≥ 30 mm, MAE increased to 9.46 mm, and all 30 compounds were underpredicted. Conclusions: Continuous-target modeling retained the IZ scale during training and generated a threshold-flexible predicted-IZ prioritization coordinate complementary to, but not statistically superior to, calibrated binary classification. The methodological contribution is a matched-data evaluation of complete workflows and their nomination behavior under the same partitions, yielding a retrospective compound-tiering scheme. Because the pipelines differed in architecture and molecular representation, their differences cannot be attributed solely to endpoint formulation. The workflows were not prospectively evaluated on compounds lacking pre-existing IZ measurements, and whether retrospective enrichment improves experimental hit discovery or reduces screening workload remains to be established. Full article
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