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Recent Submissions
Microplastic removal efficiency in a megacity water treatment plant and dynamics in the distribution system
(2025-11-01) Ta A.T.; Babel S.; Don C.D.Y.Y.A.; Ta A.T.; Mahidol University
Microplastic (MP) contamination in drinking water has emerged as a pressing environmental and public health concern. However, its behavior across treatment and urban distribution systems remains poorly understood, particularly in rapidly growing megacities. This study investigates MPs' prevalence, removal efficiency in a major water treatment plant (WTP) in Bangkok, Thailand, and through the urban water distribution network. Seasonal samples were collected at four treatment stages, clarification, filtration, and chlorination, in a conventional WTP, and at five household taps located 3–11 km downstream in the distribution system. MP concentrations in raw water reached 114 ± 46 items/L in the dry season and 56 ± 11 items/L in the rainy season. The WTP achieved an overall MP removal efficiency of 75–81 %, with filtration being the most effective stage. However, residual MPs persisted in treated water, with concentrations ranging from 14 ± 8 items/L during the rainy season to 22 ± 18 items/L in the dry season. Notably, MP levels increased significantly with distance from the WTP, peaking at 66 ± 27 items/L at the farthest household, suggesting secondary contamination within the distribution system. Fragments were the most abundant MP morphology, while PP, PE, and PET were the dominant polymer types. Small-sized MPs (<100 µm) were prevalent, raising concerns about human exposure and treatment limitations. This study highlights the need for integrated water quality management addressing both treatment efficiency and distribution infrastructure. The findings serve as a reference for improving water safety in Bangkok and other rapidly urbanizing cities worldwide.
Vector competence of Aedes albopictus for Tonate virus highlights transmission risks in temperate and tropical regions
(2025-01-01) Moltini-Conclois I.; Khanom W.; Miot E.F.; Pintong A.r.; Njifon H.L.M.; Ginebre C.; Choumet V.; Coutard B.; Mariac C.; Roques P.; Colmant A.M.G.; Piorkowski G.; Pompon J.; Missé D.; Moltini-Conclois I.; Mahidol University
Recent evidence of vertical transmission of Tonate virus (TONV) during early pregnancy and its association with fetal neurological anomalies highlights its potential public health threat. TONV is an understudied alphavirus endemic to French Guiana. The growing presence of Aedes (Ae.) albopictus in Europe raises concerns about its ability to transmit emerging arboviruses, including TONV. We assessed the vector competence of Ae. albopictus populations from mainland France and La Réunion Island via oral infections using different TONV doses. Both populations supported efficient viral replication, with infectious viral particles appearing in saliva by day 5 post-infection. Infection rate (IR), stepwise dissemination rate (sDR), and transmission efficiency (TE) increased with rising viral concentrations. At a viral concentration of 106 PFU/mL IR reached 80%, and TE at day 5 post-infection was 27% for the mainland strain and 37% for the La Réunion strain. Notably, TE declined over time in the mainland strain, while increasing progressively in the La Réunion population. Comparative infections with Chikungunya virus revealed that TONV was transmitted at similar or greater rates, confirming Ae. albopictus as a competent vector. Sequencing of mosquito organs revealed intra-host TONV genetic variability. A recurrent polymorphism at position 11,357 in the 3′UTR was detected in body tissues but not in heads of La Réunion mosquitoes, suggesting tissue-specific selection or bottlenecks. Our results demonstrate that Ae. albopictus from both tropical and temperate areas can efficiently transmit TONV and emphasize the importance of genomic surveillance to anticipate risk of its emergence in areas where this vector is established.
Vitamin B levels in older adults with pre-frailty and frailty: the impact of MTHFR and TCN2 polymorphisms and their association with global DNA methylation and physical performance
(2025-12-01) Chitta P.; Pratumvinit B.; Kaewboonruang W.; Dawangpa A.; Khamrangsee S.; Assantachai P.; Sutiwisesak R.; Wongloet W.; Tencomnao T.; Sae-Lee C.; Chitta P.; Mahidol University
Background: Frailty syndrome poses significant challenges in older populations. Understanding the genetic and biochemical factors associated with frailty is essential for effective management strategies. Methods: In this study, Thai older adults (≥ 60 years, n = 170) were assessed for physical parameters, levels of B vitamins, creatinine, and homocysteine. The polymorphisms of methylenetetrahydrofolate reductase (MTHFR) (677 C > T) and Transcobalamin II (TCN2) 776G > C were identified. Global DNA methylation (global DNAm) was assessed using a colorimetric assay. Results: Participants were categorised into robust (n = 61), pre-frail (n = 62), and frail (n = 47) groups by Fried criteria and Kihon checklist. The physical parameters, including chair stand, functional reach, gait speed, and handgrip strength, showed highly significant differences among the groups (p < 0.01). Significant differences in folate and vitamin B6 concentrations were observed between MTHFR and TCN2 genotypes, respectively. In addition, global DNAm levels were significantly lower in pre-frail individuals, particularly among those carrying the MTHFR C677T genotype, compared to both robust and frail groups. Notably, lower global DNAm was associated with a higher likelihood of being classified as pre-frail rather than frail, and a lower likelihood of being pre-frail compared to robust individuals. Moreover, correlation analyses revealed significant associations among physical parameters, clinical characteristics, and global DNAm. Conclusions: This study demonstrated the interplay between genetic variants, micronutrient status, and epigenetic modifications in the context of frailty among older adults. These findings highlight the potential of epigenetic and metabolic markers in identifying early frailty, though longitudinal and mechanistic studies are needed to further clarify causal pathways. Trial registration: This study was duly registered with the Thai Clinical Trial under the identifier TCTR20240626002 (date of registration: 21/06/2024).
Bacteriogenic metallic and semiconducting nano-system as a potential sustainable solution for one health complexities
(2025-12-01) Chaudhary V.; Sonu S.; Raizada P.; Kaushik A.; Chaudhary V.; Mahidol University
Considering the complexities of electronics waste management to meet the requirements of digital-age technologies, this article underscores the pressing need for eco-friendly, economical, and sustainable engineering solutions. Here, it uniquely focuses on bacteriogenic metallic and semiconducting nano-systems as a promising yet underexplored solution for sustainable materials innovation. Unlike conventional green nanofabrication methods involving plants or eukaryotic microbes, bacteria possess numerous merits for fabrication, including ease of cultivation, a wide spectrum of genera, abundance, prompt cell division efficacy, genetic elasticity, and high bio-reduction/oxidation efficacy that make them highly adaptable platforms for engineered nanostructures. This article provides a comprehensive and first-of-its-kind framework integrating bacterial synthesis pathways (intercellular and extracellular), bacterial class (Monoderm and Diderm), reaction parameters (pH, temperature, precursor concentration), and molecular precursors (proteins, enzymes, exopolysaccharides, redox mediators). It further highlights emerging applications of bacteriogenic nanomaterials across medicine, energy, environment, and food sectors, enabled by their antipathogenic, catalytic, anticancer, antioxidant, photocatalytic, and biocompatible properties, contributing to the betterment of One Health. Besides, this article emphasizes exploring challenges like cytotoxicity, scalability, and stability, which restrict their transformative aspects. To address these obstacles, systematic studies including in-vitro/in-vivo toxicity, lifecycle, biodistribution and bioaccumulation analyses, and predictive modelling by adopting contemporary technologies like artificial intelligence (AI), complex systems, bioinformatics, and biotechnology to bridge the laboratory-to-market gap are suggested to enrich the suggested class of nano-systems. Overall, this article not only consolidates the state-of-the-art but also presents a novel interdisciplinary vision where bacterial complexity drives next-generation nanoengineering, aligning with the United Nations' sustainability goals.
In vitro activity of sulbactam in combination with other antimicrobial agents against extensively drug-resistant Acinetobacter baumannii
(2025-09-01) Jitmuang A.; Tiengrim S.; Thamlikitkul V.; Koomanachai P.; Jitmuang A.; Mahidol University
Extensively drug-resistant (XDR) Acinetobacter baumannii infection has significant challenges due to limited treatment options. Although sulbactam (SUL) shows in vitro effectiveness against XDR A. baumannii, the efficacy of SUL-based combinations remains unclear. This investigation aimed to delineate the in vitro activity of SUL combined with various antimicrobial agents against XDR A. baumannii. Sixty-two clinical isolates of XDR A. baumannii were tested for minimal inhibitory concentrations (MICs) of SUL, amikacin (AMI), ciprofloxacin, colistin (COL), fosfomycin (FOS), gentamicin, meropenem (MER), rifampicin (RIF), sitafloxacin (SIT), and tigecycline (TIG) using broth microdilution. The checkerboard method, employing the fractional inhibitory concentration index, assessed in vitro synergy between the SUL-based combination. Time–kill analyses of selected isolates were conducted to measure log10 colony-forming unit per milliliter growth changes over 24 hours between individual and combined agents. The SUL MICs ranged from <4 to 256 mg/L, with an MIC50 of 64 mg/L. MIC ranges were lower for TIG (0.12–4.0 mg/L) and COL (0.5–2.0 mg/L), but higher for FOS (64–>512 mg/L). Synergism was evident in the combinations of SUL/FOS (41.9%), SUL/AMI (19.3%), SUL/MER (17.7%), SUL/RIF (14.5%), SUL/TIG (12.9%), SUL/COL (6.5%), and SUL/SIT (4.8%). Only 1.6%–3.2% of the combinations exhibited antagonism. In the time–kill assays, a combination of SUL/FOS/AMI/MER exhibited sustained bactericidal activity at 24 hours against the two isolates, whereas two- and three-agent combinations showed varying degrees of synergism. Combining SUL with available antimicrobial agents had varying degrees of synergistic effect against XDR A. baumannii. Notably, the clinical utility of SUL-based combination therapy for XDR A. baumannii infections requires further exploration.