Community carriage of extended-spectrum β-lactamase (ESBL)-producing Escherichia coli represents an important reservoir of antimicrobial resistance. However, the genomic diversity and population structure of ESBL-producing E. coli circulating in community settings remain poorly characterized. This study aimed to characterize ESBL-producing E. coli isolated from fecal samples of residents in Ecuador, with an emphasis on the diversity and genomic context of ESBL genes. ESBL-producing E. coli was isolated from fecal samples obtained from 55 residents using MacConkey agar supplemented with cefotaxime. Whole-genome sequencing of the isolates was performed using a hybrid approach combining long- and short-read platforms. Plasmids and β-lactamase genes were identified using DFAST and PlasmidFinder. Bacterial identification and antimicrobial susceptibility testing were conducted by MALDI-TOF MS and the broth microdilution method, respectively. ESBL-producing E. coli were isolated from 35 of 55 fecal samples (63.6%). Complete circular genomes were obtained from 31 isolates. All isolates harbored bla CTX-M genes, predominantly belonging to the bla CTX-M-1 group, whereas 65.7% carried bla TEM, mainly bla TEM-1, and related variants. Although β-lactamase genes were predominantly plasmid-borne, chromosomal integration was detected in 40% of the isolates. Notably, 87.5% of the isolates harbored IncF plasmids with multiple replicons. Conserved IS26-flanked transposons carrying bla CTX-M and bla TEM were frequently identified in the plasmids. Phylogenetic analysis revealed substantial genomic diversity across seven phylogroups, together with closely related isolates detected within and between households. These findings provide high-resolution genomic insights into the ESBL determinants circulating in community residents and reveal region-specific patterns of ESBL genomic diversity.
Pseudomonas aeruginosa is an important cause of surgical site infections (SSIs) and is characterized by extensive antimicrobial resistance and genomic plasticity. We analyzed 13 whole-genome sequences of clinical P. aeruginosa isolates recovered from SSIs at a Level 5 referral hospital in Western Kenya and integrated genomic analyses with antimicrobial susceptibility tests and phenotyping of quorum-sensing (QS). Multidrug resistance was common, with resistance observed primarily against ciprofloxacin, piperacillin, ceftazidime, and amikacin, whereas meropenem and piperacillin/tazobactam retained the greatest in vitro activity. Genomic analyses identified diverse sequence types, extensive variability in insertion sequences and genomic islands, and widespread conservation of intrinsic resistance determinants, whereas accessory antimicrobial resistance genes were infrequently detected and largely associated with genomic islands. Virulence-associated genes were predominantly chromosomal, although several showed strain-specific genomic island localizations. Functional QS analyses demonstrated that isolates with intact lasR and rhlR produced significantly higher levels of acyl-homoserine lactone signals than isolates carrying predicted loss-of-function mutations, whereas Pseudomonas quinolone signal production remained comparatively conserved. These findings provide a genomic baseline for P. aeruginosa causing SSIs in Western Kenya and highlight the importance of integrating whole-genome sequencing with phenotypic analyses to strengthen surveillance and inform antimicrobial stewardship and infection prevention strategies.
Shiga toxin-producing Escherichia coli (STEC) colonizes the bovine recto-anal junction (RAJ), a key step in STEC pathogenesis in cattle, associated with animal disease, persistence, fecal shedding, carcass contamination, and zoonotic transmission. However, early adhesion mechanisms at the bovine RAJ remain insufficiently characterized, particularly among serotypes lacking the Locus of Enterocyte Effacement (LEE), referred to as LEE-negative strains. This study investigated strain-dependent epithelial interaction patterns at the bovine RAJ using complementary in vitro, ex vivo, and transcriptional approaches. Four representative strains were selected for functional assays, including two LEE-positive strains (O157:H7 and O26:H11) and two LEE-negative strains (O113:H21 and O130:H11). All strains adhered to primary bovine RAJ squamous epithelial cells, although no significant quantitative differences were detected among strains. In RAJ explants, however, LEE-positive strains showed epithelial association extending beyond the superficial layer, with immunolabeling distributed across the epithelial regions, whereas LEE-negative strains showed a predominantly superficial distribution. This pattern, not previously described in bovine RAJ explants, expands the current view of STEC colonization as a uniformly superficial epithelial process. Analysis of selected adhesion-related genes revealed strain-dependent transcriptional responses to the RAJ environment. LEE-positive strains showed higher expression of eae, together with increased expression of iha, csgD, and pgaA. In contrast, LEE-negative strains showed lower expression of these genes and consistent expression of saa, supporting the existence of distinct epithelial interaction strategies that may reflect strain-specific behaviors among circulating LEE-positive and LEE-negative isolates. Overall, these findings demonstrate distinct epithelial interaction and transcriptional profiles among STEC strains and show that physiologically relevant tissue models can reveal serotype-dependent colonization patterns not fully captured in simplified cell systems and may support the identification of potential targets for vaccine-based intervention strategies in cattle.
Ascidians are filter-feeding marine invertebrates that display inter- and intraspecific color variation and host diverse microbiomes. Although color variation has been used as an indicator of speciation and correlated with distinct microbiome structure in some colonial species, there is limited research on microbiome variation across color morphs and body regions in solitary ascidians. To address these knowledge gaps, three color morphs (purple, orange, and intermediate shades of pink) of the solitary Belizean ascidian Rhopalaea abdominalis were collected for phylogenetic analysis using the Cytochrome Oxidase I (COI) gene and for microbial characterization via sequencing the V4 region of the 16S rRNA gene. Microbial sequences derived from the ascidian branchial sac, gut, and tunic body regions were processed using both operational taxonomic unit (OTU) and amplicon sequence variant (ASV) pipelines to determine the resolution and consistency of sequence processing methods using mothur and QIIME 2 software, respectively. COI sequencing revealed two clades that were independent of color morphs. Microbiome characterization showed no significant differences in alpha- or beta-diversity across ascidian color morphs or COI clades but distinct microbiomes within each body region. The branchial sac harbored a higher number of core members (i.e., detected across all host individuals) that included known ascidian symbionts (e.g., Endozoicomonas), whereas the gut and tunic were colonized by taxa identified in seawater and across multiple classes of marine invertebrates. Results were highly congruent between OTU- and ASV-based pipelines, yielding statistically equivalent alpha-diversity metrics, consistent beta-diversity patterns, and similar core membership profiles. These findings reinforce the validity of both methods for studying microbial symbiont communities and corroborate previous research showing distinct microbiomes by body region and overall conservation when color morphs lack genetic differentiation.
Tropical peatlands are among the largest global carbon sinks and face increasing impacts from drainage, fire, and land-use change. These disturbances modify soil physicochemical characteristics and influence bacterial community structure. However, the response of bacterial communities to these changes is incompletely understood. This study examined bacterial community composition at six peatland sites in the Giam Siak Kecil-Bukit Batu Biosphere Reserve, Riau, Indonesia. The sites represent various land-use types: secondary forest, restored peat, burned peat, oil palm, rubber, and acacia plantations. The analysis employed 16S rRNA gene sequencing combined with measurements of soil physicochemical properties. Results showed that key bacterial phyla, such as Acidobacteriota, Pseudomonadota, and Actinomycetota, were consistently found across sites, though their relative abundances varied. Burned sites had increased abundances of Bacillota and other copiotrophic groups and decreased abundances of several oligotrophic taxa. Beta diversity analysis showed differences in community patterns among sites, but multivariate analysis did not show significant differences between land-use types. Variation in bacterial community composition is associated with soil pH and nutrient availability, including available phosphorus, exchangeable potassium, and exchangeable magnesium, although these relationships are not always statistically supported. A small number of ASVs were detected across all sites, suggesting overlapping community members amid high spatial heterogeneity. Overall, tropical peatland bacterial communities form within a narrow environmental framework in which distinctive physicochemical properties constrain which microbes can survive. Land-use changes are primarily associated with shifts in the relative abundance of bacterial taxa rather than complete community turnover. Given the limited number of samples and single time-point observations, these findings are exploratory and provide a basis for further research.
Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of multidrug-resistant and biofilm-associated infections, particularly on indwelling medical devices, where conventional antibiotics often exhibit limited efficacy. In this study, we isolated and characterized a novel lytic bacteriophage, SA_SGEB_01, targeting MRSA from hospital wastewater in Bangladesh. Biological characterization demonstrated that SA_SGEB_01 possesses favorable therapeutic properties, including a short latent period (~45 min), a burst size of approximately 91 plaque-forming units per infected cell, and stability across a broad pH range (3-11) and temperatures up to 45°C. Host range analysis revealed lytic activity against MRSA and methicillin-resistant Staphylococcus saprophyticus. Whole-genome sequencing showed that SA_SGEB_01 contains a linear double-stranded DNA genome of 18,031 bp with no detectable lysogeny-associated, antibiotic resistance, or virulence genes, supporting its therapeutic suitability. Comparative genomic and phylogenetic analyses classified the phage within the genus Rosenblumvirus of the family Rountreeviridae. Phage-antibiotic checkerboard assays demonstrated strong synergistic activity between SA_SGEB_01 and ciprofloxacin, with fractional inhibitory concentration index values below 0.5. Importantly, SA_SGEB_01 significantly reduced biofilm biomass in both 24- and 48-h-old MRSA biofilms and achieved approximately a 2-log10 reduction of viable cells in in vitro silicone catheter-associated biofilms, whereas vancomycin did not produce a statistically significant reduction under the same experimental conditions. To our knowledge, this is the first biologically and genomically characterized S. aureus phage from Bangladesh with demonstrated activity against MDR MRSA biofilms, highlighting its potential as a promising candidate for controlling device-associated MRSA infections.
The growing threat of antimicrobial resistance (AMR) among foodborne pathogens poses a significant public health risk in South Africa, largely driven by excessive antibiotic use in dairy farming practices. This study investigated the virulence and AMR profiles of Escherichia coli isolated from bovine quarter milk samples in the Dr. Kenneth Kaunda District, North West Province, South Africa. Sixty-five E. coli isolates were confirmed using the automated identification Sensititre ARIS 2X ID/AST System and PCR targeting the uidA gene. Serogrouping revealed a predominance of non-O157 strains, with O128 (50.8%) as the dominant serogroup, followed by O145 (9.2%), whereas 40% of isolates were nontypable, highlighting serotype diversity. The fliC gene encoding flagellin was the most prevalent virulence marker (62.5%), whereas stx1 was detected in 9.2% of isolates, and stx2 was absent. Phenotypic testing demonstrated high resistance to amoxicillin/clavulanic acid and cephalothin (58.9% each), tetracycline (37.8%), and trimethoprim-sulfamethoxazole (3.3%). However, no isolates exhibited phenotypic multidrug resistance (MDR), despite 98.5% harboring one or more resistance genes: ermB (92.3%), vanB (90.8%), tetM (56.9%), and ampC (10.8%). The high prevalence of ermB and vanB may indicate coselection of resistance determinants and suggests their potential association with mobile genetic elements that facilitate dissemination among bacterial populations. These findings indicate that E. coli from bovine milk in the region serve as silent reservoirs for virulence and resistance genes. These findings are vital for managing E. coli isolates in dairy farming and taking proactive measures to limit AMR in animals.
Background:Candida is one of the most common causes of bloodstream infections in critically ill and immunocompromised patients. Understanding the distribution and antifungal resistance patterns of Candida species and the associated mortality rates is critical for tailoring therapeutic measures. Objectives:The aim of this study is to analyze the epidemiology, antifungal resistance trends, and risk factors influencing mortality associated with candidemia in a tertiary healthcare center of Saudi Arabia. Patient and Methods:The study included all cases of bloodstream infections caused by Candida species from December 2021 to January 2023. The antifungal susceptibility and identification of species were done via standard protocols. Univariate and multivariate statistical analyses were conducted to determine the predictors of 14-day mortality (death within 14 days of the first positive blood culture) and overall (in-hospital) mortality (death during the index hospitalization). Results:Fifty patients were included in the study with a median age of 71 years, with 58% being females. C. albicans accounted for 21.3% of candidemia cases, with a declining trend over time. Candidozyma auris (formerly Candida auris) was the most frequently identified non-albicans Candida species (25%). Fluctuating trends in antifungal susceptibility of non-albicans Candida were observed, with increasing resistance to azoles, while increasing susceptibility to micafungin. The 14-day mortality and overall (in-hospital) mortality rates were 23.4% and 55.3%, respectively. Multivariate analysis revealed older age, cardiac and respiratory disorders, ICU as site of diagnosis, treatment duration of > 48 h, and Candida colonization to be independent predictors of overall (in-hospital) mortality (p < 0.05). Conclusion:The continuous rise of antifungal resistance and spread of non-albicans Candida species highlight the need for implementing rigorous control measures in healthcare facilities. Improving candidemia outcomes requires prompt identification of high-risk patients and targeted therapies.
Antimicrobial resistance (AMR) in foodborne pathogens represents a major public health concern, particularly in traditional animal-derived foods. This study investigated the occurrence of β-glucuronidase-positive Escherichia coli and methicillin-resistant Staphylococcus aureus (MRSA) in 121 meat products and 328 cheeses produced in the province of Cosenza (Calabria, Southern Italy). Microbiological analyses were performed according to ISO 16649-2:2001 and ISO 6888-2:2021, and isolates were biochemically confirmed using the Vitek 2 System. Thirty cheese samples exceeded regulatory limits for coagulase-positive staphylococci, while 29 showed elevated Escherichia coli counts, likely associated with raw milk use and artisanal processing. Among meat products, only two fresh sausages tested positive for Escherichia coli, suggesting contamination linked to inadequate sanitation of casings. Statistical analyses revealed significantly higher positivity rates for both microorganisms in cheese compared with meat products. These findings highlight the need for improved hygiene practices, continuous monitoring, and targeted interventions to reduce microbial contamination in traditional foods. Enhanced surveillance is also essential to track the emergence and dissemination of MRSA in the food chain.
Meningitis, an acute and life-threatening inflammation of the protective membranes covering the brain and spinal cord caused primarily by bacterial, viral, fungal, or parasitic infections, remains a major global health challenge, causing significant morbidity and mortality, particularly among children and vulnerable populations. The Sri Lankan epidemiological unit reported approximately 1000-1500 meningitis cases annually. This review summarizes current knowledge on meningitis in Sri Lanka, drawing on global evidence and locally published studies to examine epidemiology, clinical presentation, diagnostic approaches, immunity gap, and future priorities. Most studies indicate that bacterial meningitis, particularly caused by Streptococcus pneumoniae, Neisseria meningitidis, and Haemophilus influenzae, remains the most severe and clinically significant form. Viral etiologies, especially enteroviruses, are also commonly reported. Although the introduction of the H. influenzae Type b (Hib) vaccine has significantly reduced disease burden, important immunity gaps persist due to limited pneumococcus serotype coverage and the absence of routine meningococcal vaccination. Diagnostic challenges, including delays in cerebrospinal fluid collection, limited access to molecular testing, and preanalytical errors, hinder early detection and accurate pathogen identification. Future directions should focus on strengthening molecular diagnostic capacity, strengthening point-of-care rapid antigen assays and decentralized molecular diagnostics, expanding serotype surveillance, improving sample collection practices, and evaluating the feasibility of introducing meningococcal vaccination into the national immunization schedule. Bridging these gaps is essential for aligning Sri Lanka's efforts with global targets outlined in the World Health Organization's (WHO) Defeating Meningitis by 2030 roadmap.
Brucellosis is a neglected zoonosis with a considerable disease burden in livestock-dependent areas. Khuzestan Province, southwestern Iran, exhibits diverse ecological and agricultural landscapes that may drive heterogeneous transmission. Knowledge of recent epidemiological trends is important for targeted control. We aimed to characterize the temporal and demographic patterns of human brucellosis in Khuzestan from 2017 to 2024, with emphasis on changes observed after 2021. We analyzed aggregated surveillance data for all laboratory-confirmed human brucellosis cases reported in Khuzestan Province between 2017 and 2024. Crude annual incidence rates were calculated using population denominators linearly interpolated from the 2017 census and the 2023 official estimate. Log-linear trend regression, performed using Joinpoint software, estimated the annual percentage changes (APCs) in incidence case counts. Poisson's regression with population offset quantified period relative risks (RRs) comparing 2022-2024 with 2017-2021. Chi-square tests assessed temporal shifts in distributions across age groups (15 categories), sex, residence (rural/urban/nomadic), and four geographical zones (Northern Highlands, Central Plains, Southern Coastal and Marshland, and Western Borderlands). A total of 3923 cases were reported. Crude incidence remained stable at 7.9-8.1 per 100,000 during 2017-2019, declined to 6.3-7.0 in 2020-2021, and then increased sharply to 12.3-14.7 in 2022-2024 (APC = +10.7%; 95% CI: 2.2-19.9; p = 0.019). Incidence during 2022-2024 was 1.66 times higher than during 2017-2021 (95% CI: 1.52-1.81; p < 0.001). The largest relative increases in reported case counts were in adults aged ≥ 70 years (APC = +21.1%; 95% CI: 11.1-32.2) and in adults aged 65-69 years (+20.0%, 9.9-31.1), whereas children aged 0-4 years showed no significant change. The male-to-female ratio shifted from 0.88 in 2017 to 1.22 in 2024 (p = 0.032), driven by a significant rise in male cases (APC = +11.5%, p = 0.011) against a nonsignificant female increase. Rural cases increased significantly (APC = +11.2%, p = 0.009), accounting for 47%-61% of annual cases. The Northern Highlands zone bore 62.7% of total cases (APC = +11.6%, p = 0.003); the Southern Coastal zone exhibited the steepest relative increase (APC = +15.8%, p = 0.020). Although statistically significant, changes in composition over time were small in magnitude (Cramér's V = 0.06 - 0.12). Human brucellosis in Khuzestan Province has resurged dramatically since 2021, with a 66% increase in period risk. The epidemiological profile shifted to older adults, males, and people living in rural areas, with marked geographical heterogeneity. The results emphasize the need for targeted vaccination of livestock in high-burden areas (Northern Highlands and Southern Coastal), enhanced surveillance in older age groups, and increased One Health approaches to reverse this trend.
Paronychia represents an underexplored clinical condition with limited alternatives to conventional antimicrobial therapies, which are increasingly compromised by antibiotic resistance and toxicity. Here, we report for the first time the extracellular biosynthesis of silver nanoparticles (BAgNPs) using Bacillus stercoris 2AT10, a marine-derived bacterium not previously exploited for nanoparticle production. By integrating green nanotechnology with genome mining approaches, we investigated the molecular basis underlying nanoparticle formation and evaluated the potential of BAgNPs against pathogens associated with paronychia. Physicochemical characterization by ultraviolet-visible (UV-Vis) spectroscopy confirmed the presence of particles, with mean sizes ranging from 47 to 87 nm measured by dynamic light scattering (DLS). Their spherical shape was confirmed by transmission electron microscopy (TEM), whereas Fourier-transform infrared (FTIR) spectroscopy suggested the presence of hydroxyl, amide, and nitrogen-containing groups possibly associated with reducing or capping action. Genes encoding nitrate reductases, laccases, and bioactive secondary metabolites, such as bacillibactin, subtilosin A, bacillaene, bacilysin and fengycin, that may be involved in silver ion reduction and nanoparticle stabilization were identified by genome annotation using eggNOG-mapper and antiSMASH. The biosynthesized AgNPs exhibited potent broad-spectrum antimicrobial activity against paronychia-associated pathogens, notably with inhibition zones of 25.8 mm for Staphylococcus aureus and of 23.2 mm for Pseudomonas aeruginosa. The Hen's Egg Test on the Chorioallantoic Membrane (HET-CAM) assay showed the nonirritating profile of the biosynthesized particles (irritation index ≤ 1), supporting further investigation of their suitability for topical applications, pending additional biocompatibility studies. Collectively, these findings establish B. stercoris-derived BAgNPs as a promising green nanotechnology platform to address the unmet need for safe and effective prophylactic agents against bacteria associated with paronychia, with additional potential as antimicrobial preservatives for dermocosmetic formulations.
This study is aimed at isolating and characterizing antimicrobial peptides (AMPs) from the leaves of Capsicum annuum (L.) cv. Carioquinha and investigating their antifungal activity and mechanism of action against phytopathogenic fungi. An initial extract was obtained from leaves through hydromethanolic extraction followed by partitioning with dichloromethane. The extract was resuspended in aqueous acetonitrile and centrifuged to obtain the soluble supernatant fraction (ExS). The ExS fraction was purified by reverse-phase high-performance liquid chromatography (RP-HPLC). Protein bands from the ExS fraction were excised from Tricine-SDS-PAGE gels and analyzed by LC-MS/MS. The obtained peptide sequences were compared with protein databases. Antifungal activity of the ExS fraction was evaluated through quantitative fungal growth inhibition assays against the phytopathogenic fungi Fusarium solani, Fusarium oxysporum, Colletotrichum gloeosporioides, and Colletotrichum scovillei, and tests were conducted to investigate the mechanism of action of the peptides present in the ExS fraction. RP-HPLC analysis of the ExS fraction revealed a single peak (P1) corresponding to a protein band of approximately 6.5 kDa, and all fragments obtained by LC-MS/MS were similar to peptides belonging to the hevein-like family. The highest inhibition was observed for C. gloeosporioides, with 78.3% growth inhibition at 200 μg mL-1. Mechanistic studies revealed that the ExS fraction caused membrane permeabilization in C. gloeosporioides, induced reactive oxygen species (ROS) production, and reduced cell viability. The ExS fraction also caused vacuolization of hyphae in F. oxysporum. This study highlights the potential of AMPs isolated from C. annuum leaves to inhibit phytopathogenic fungi.
Pleurotus eous (P. eous) contains a range of bioactive metabolites with reported antimicrobial and antioxidant potential. This work describes the green synthesis of silver nanoparticles using an aqueous extract of P. eous and evaluates their physicochemical features and in vitro antimicrobial activity. Silver nanoparticles were formed through fungal extract-mediated reduction of silver nitrate, with UV-visible spectroscopy showing a surface plasmon resonance band around 420 nm. FTIR analysis indicated the involvement of fungal biomolecules in reduction and stabilization, while XRD confirmed the crystalline, face-centered cubic structure of metallic silver. FE-SEM imaging revealed predominantly spherical nanoparticles with an average size of 39 ± 7.6 nm. The methanolic extract of P. eous showed strong antioxidant activity, with DPPH radical scavenging reaching 97.39%, and contained measurable phenolic content (1.02 ± 0.07 mg GAE g-1 dry weight), as supported by GC-MS profiling. Antimicrobial testing demonstrated that the biosynthesized silver nanoparticles exhibited moderate inhibitory effects against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Candida tropicalis, and Aspergillus niger, with inhibition zones of 11.8-16.3 mm for bacteria and 13.3-14.3 mm for fungi at 250 μg. While less potent than conventional antimicrobials, these nanoparticles demonstrated measurable activity, warranting detailed toxicity and in vivo evaluation.
Microbially induced carbonate precipitation (MICP) is a recognized bioremediation strategy for mitigating toxic metal pollution; however, the relative contributions of bioprecipitation, biosorption, and bioaccumulation to cadmium (Cd) removal during MICP remain underexplored. This study assessed Cd immobilization by six rhizosphere ureolytic bacterial strains from different genera in liquid medium and quantified the metal distributed among the bioprecipitated, biosorbed, and bioaccumulated fractions. Minimum inhibitory concentration assays showed Cd tolerance ranging from 90 to 300 mg L-1. The strains presented total Cd removal efficiencies of 64.9%-99.8% within 120 h. Notably, Cd removal occurs mainly under 48 h. Biosorption assays revealed substantially lower Cd removal compared with bioprecipitation experiments. Comparative analysis of Cd bioprecipitation and biosorption assays, combined with sequential extraction, demonstrated that bioadsorption plays a significant role in the removal of Cd via MICP. Precipitates characterization further confirmed coprecipitation of Cd with vaterite, a calcium carbonate polymorph. These findings elucidate an important role of biosorption in Cd immobilization during MICP, highlighting the need to evaluate removal mechanisms when assessing bacterial MICP potential, as different mechanisms can lead to distinct long-term stability outcomes.
Atopic dermatitis (AD) is a chronic inflammatory skin disorder characterized by microbial imbalance, particularly the overgrowth of Staphylococcus aureus. This study reports the green synthesis of silver nanoparticles (AgNPs) using Macaranga tanarius extract (MTE) and evaluates their in vitro antibacterial and bioactive properties. The synthesized MT-AgNPs exhibited a distinct surface plasmon resonance (SPR) peak at 430 nm, with TEM revealing predominantly spherical morphologies (mean size: 29.2 nm; range: 6-87 nm). Phytochemical analysis confirmed that MTE is rich in polyphenols (2429 ± 33.7 mg GAE/100 g) and flavonoids (236.3 ± 10.7 mg QE/100 mL), contributing to its strong antioxidant capacity (82.72% ± 3.12% DPPH scavenging; FRAP: 20.36 ± 0.02 mg FeSO4/100 mL). MT-AgNPs demonstrated potent antibacterial activity against 17 clinical S. aureus isolates (e.g., mecA-positive strains), with MICs of 9.375-18.75 μg/mL. At 6.25 μg/mL, MT-AgNPs significantly inhibited biofilm formation by up to 63% (p < 0.05). Crucially, MTE displayed a highly stable tyrosinase inhibitory profile, maintaining a consistent inhibition rate of approximately 45% throughout a 120-min kinetic assay (equivalent to 6.0-8.5 mg kojic acid/g). This sustained inhibitory stability suggests its potential application in addressing postinflammatory hyperpigmentation. These findings indicate that MT-AgNPs serve as a promising, eco-friendly antibacterial nanomaterial with potential in vitro applications for managing AD-related microbial challenges and skin recovery.
Background:Acute appendicitis is one of the most common surgical emergencies in children. In complicated appendicitis, timely empirical antimicrobial treatment is important, but antimicrobial selection is increasingly affected by regional variation in pathogen distribution and resistance. This study characterized the aerobic and facultative bacterial isolates recovered from intraoperative purulent specimens obtained from pediatric patients with acute appendicitis and described their antimicrobial susceptibility patterns. Methods:This prospective observational study enrolled 70 consecutive pediatric patients who underwent appendectomy for acute appendicitis at the Second Affiliated Hospital of Fuyang Normal University between January 2024 and January 2025. Intraoperative purulent material was collected using sterile swabs and processed by routine aerobic culture methods. No dedicated anaerobic culture or culture-independent molecular analysis was performed. Bacterial identification was conducted using the VITEK 2 Compact system. Antimicrobial susceptibility testing was performed using broth microdilution and interpreted according to the applicable Clinical and Laboratory Standards Institute criteria. Extended-spectrum β-lactamase production among Escherichia coli isolates was confirmed using the double-disk synergy test. Appendicitis was operationally categorized as uncomplicated or complicated according to operative and pathological findings. Results:Aerobic or facultative bacterial growth was detected in 62 of 70 specimens, corresponding to a culture-positive rate of 88.6% (95% confidence interval, approximately 78.2%-94.0%). A total of 62 isolates were recovered from the 62 culture-positive specimens, and no polymicrobial aerobic or facultative growth was recorded using the applied culture strategy. Gram-negative organisms accounted for 61 of 62 isolates (98.4%). E. coli was the predominant isolate (46/62, 74.2%), followed by Pseudomonas aeruginosa (9/62, 14.5%). Nineteen of the 46 E. coli isolates (41.3%) were ESBL producers. E. coli retained high in vitro susceptibility to amikacin and imipenem but showed substantial resistance to ceftriaxone and trimethoprim-sulfamethoxazole. All nine P. aeruginosa isolates were susceptible to the antimicrobial agents tested. Based on the revised clinical classification, nine patients had uncomplicated appendicitis and 61 had complicated appendicitis. Conclusions:The organisms recovered with the present culture strategy were predominantly aerobic or facultative gram-negative bacteria, especially E. coli, and ESBL production was frequent among E. coli isolates. These findings provide local surveillance information that may support antimicrobial stewardship and the reassessment of empirical coverage in pediatric appendicitis. However, because anaerobic culture, treatment comparisons, and comprehensive outcome analyses were not performed, the study does not characterize the complete appendiceal microbiota or establish the superiority of a specific empirical antimicrobial regimen.
Indwelling medical devices represent an impressive stride in modern surgical practice and are widely used in procedures that support the body's natural physiological functions. The global demand for these devices has surged, primarily driven by a range of clinical and demographic factors. However, their widespread use also carries risks, as foreign devices can introduce pathogens into the body during surgery and implantation. Shortly after implantation, host-derived conditioning films rapidly coat the device surface, creating a foundation for bacterial attachment and subsequent biofilm formation. Biofilms are complex communities of microbial cells embedded within extracellular polysaccharide matrices on device surfaces. Bacteria within biofilms exhibit high resistance to antibiotics and host immune defenses, posing significant challenges for detection and diagnosis, largely due to the protective structural barrier and associated physiological changes. Biofilm-associated device infections are persistent, chronic, and difficult to treat, often leading to treatment failure and recurrent infections. Recurring device-related infections and repeated surgical interventions impose severe pain and substantial financial burdens on patients. Moreover, biofilms can induce device “corrosion,” compromising biocompatibility with surrounding tissues and shortening implant lifespan. Overall, bacterial attachment and biofilm formation on medical devices are notorious problems, causing device-associated infections, device malfunction, and significant economic losses. Therefore, this review is aimed at providing an overview of biofilm formation on indwelling medical devices and its implications on health and economy.
Urinary tract infections (UTIs) are among the most common bacterial infections worldwide. Although Gram-negative bacteria predominate, Gram-positive cocci (GPC) are increasingly recognized as significant uropathogens. This retrospective study analyzed 655 patients with culture-confirmed GPC UTIs in a hospital in Central Portugal (2018-2022) to identify predictors of multidrug resistance (MDR). MDR was defined as resistance to three or more antimicrobial classes. The overall MDR prevalence was 83.7%, with Enterococcus spp. showing the highest MDR prevalence (98.2%). Multivariate analysis identified older age as an independent predictor of MDR, whereas Staphylococcus and Streptococcus species were associated with significantly lower odds compared to Enterococcus. A temporal increase in MDR risk was observed in 2021 and 2022. Despite the high overall resistance rates observed, oxazolidinones and cyclic lipopeptides retained near-complete activity against all GPC isolates, reinforcing their role as last-line therapeutic options.
Aporosa octandra var. malesiana is a native Sumatran plant traditionally used in treating throat-related conditions, indicating a rich reservoir of bioactive constituents. Endophytic microorganisms are known to produce metabolites similar to those found in medicinal plants. Therefore, this study explores the metabolomic fingerprint and antibacterial activity of an endophytic bacterium isolated from Aporosa octandra var. malesiana and examines its molecular interactions with key antitonsillitis targets through in silico approaches. In total, 44 endophytic bacterial isolates were obtained, of which 12 exhibited antagonistic activity against Streptococcus pyogenes. 16S rRNA gene-based molecular and phylogenetic analyses identified the isolate as Streptomyces luteolus. Metabolomic profiling using LC-MS/MS identified 4-(dimethylamino)pyridine (4-DMAP) and nicotinic acid as the two predominant metabolites. In silico docking analysis showed that these compounds interact with DNA gyrase and penicillin-binding protein via hydrogen bonding and hydrophobic interactions, indicating their potential to inhibit essential bacterial processes. These results highlight Streptomyces luteolus associated with Aporosa octandra var. malesiana as a promising reservoir of antibacterial metabolites and support further studies to evaluate their potential against tonsillitis-associated pathogens.
