Algal extracellular organic matter mediated photocatalytic degradation of estrogens.

Estrogens are among the most concerned emerging contaminants in the wastewater treatment effluent due to their sexual disruption in aquatic wildlife. The use of microalgae for secondary wastewater effluent polishing is a promising approach due to the economic benefit and value-added products. In this study, three microalgae species, including Selenastrum capricornutum, Scenedesmus quadricauda and Chlorella vulgaris were selected to conduct batch experiments to examine important mechanisms, especially the role of algal extracellular organic matter (AEOM) on two selected estrogens (17ß-estradiol, E2 and 17α-ethynylestradiol, EE2) removal. Results showed that estrogens could not be significantly degraded under visible light irradiation and adsorption of estrogens by microalgae was negligible. All three living microalgae cultures have ability to remove E2 and EE2, and Selenastrum capricornutum showed the highest E2 and EE2 removal efficiency of 91% and 83%, respectively, corresponding to the reduction of predicted estrogenic activity of 86%. AEOM from three microalgae cultures could induce photodegradation of estrogens, and AEOM from Selenastrum capricornutum and Chlorella vulgaris achieved 100% of E2 and EE2 removal under visible light irradiation. Fluorescence excitation-emission matrix spectroscopy identified humic/fulvic-like substances in AEOM from three microalgae cultures, which might be responsible for inducing the indirect photolysis of E2 and EE2. Therefore, in the living microalgae cultures, the major estrogens removal mechanisms should include biotransformation as well as AEOM meditated photocatalytic degradation. Since removal rates through photodegradation could be faster than biotransformation, the AEOM mediated photocatalytic degradation can play a potential role to remove emerging contaminants when using microalgae technology for wastewater effluent treatment.

Characteristics of Carbapenemase-Producing Enterobacteriaceae in Wastewater Revealed by Genomic Analysis.

Wastewater is considered a major source of antibiotic-resistant bacteria released into the environment. Here, we characterized carbapenemase-producing Enterobacteriaceae (CPE) in wastewater by whole-genome analysis. Wastewater samples (n = 40) were collected from municipal wastewater treatment plants and hospital wastewater in Japan and Taiwan. Samples were screened for CPE using selective media, and the obtained isolates were sequenced using an Illumina MiSeq. The isolates (n = 45) included the following microorganisms: Klebsiella quasipneumoniae (n = 12), Escherichia coli (n = 10), Enterobacter cloacae complex (n = 10), Klebsiella pneumoniae (n = 8), Klebsiella variicola (n = 2), Raoultella ornithinolytica (n = 1), Citrobacter freundii (n = 1), and Citrobacter amalonaticus (n = 1). Among the 45 isolates, 38 harbored at least one carbapenemase-encoding gene. Of these, the blaGES (blaGES-5, blaGES-6, and blaGES-24) genes were found in 29 isolates. The genes were situated in novel class 1 integrons, but the integron structures were different between the Japanese (In1439 with blaGES-24 and In1440 with blaGES-5) and Taiwanese (In1441 with blaGES-5 and In1442 with blaGES-6) isolates. Other carbapenemase-encoding genes (blaVIM-1, blaNDM-5, blaIMP-8, blaIMP-19, and blaKPC-2) were found in one to three isolates. Notably, class 1 integrons previously reported among clinical isolates obtained in the same regions as the present study, namely, In477 with blaIMP-19 and In73 with blaIMP-8, were found among the Japanese and Taiwanese isolates, respectively. The results indicate that CPE with various carbapenemase-encoding genes in different genetic contexts were present in biologically treated wastewater, highlighting the need to monitor for antibiotic resistance in wastewater.

Azole-resistant Aspergillus fumigatus isolates carrying TR34/L98H mutations in Taiwan.

Cumulative evidence described the emergence and geographical expansion of azole-resistant A. fumigatus associated with azole treatment failure. To investigate the status of azole resistance in A. fumigatus in Taiwan, we studied 38 A. fumigatus clinical isolates cultivated from 31 patients at two teaching hospitals from 2011 to 2014. Three isolates obtained from respiratory samples of two azole-naïve patients with pulmonary aspergillosis were found to display multi-azole resistance and cross resistance to agricultural azole fungicides, and all carried TR34/L98H mutations in cyp51A gene. The prevalence rates of azole resistance were 7.9% and 6.5% based on isolates and patients respectively. A phylogenetic analysis suggested genetic diversity of the TR34/L98H isolates in Taiwan, including a unique genotype distinct from strains outside Taiwan. The result underlines the emergence of such isolates in Taiwan as well, emphasising the importance of further surveillance for azole-resistant A. fumigatus and implementation of strategies that prevent fungicide-driven resistance selection.

Transformation of bisphenol A and alkylphenols by ammonia-oxidizing bacteria through nitration.

Transformation of bisphenol A (BPA) by ammonia-oxidizing bacteria (AOB) Nitrosomonas europaea ATCC 19718 was investigated. On the basis of the ultraperformance liquid chromatography (UPLC) coupled to quadrupole time-of-flight mass spectrometry (Q-TOF MS) and nuclear magnetic resonance analysis, we found N. europaea could transform BPA into nitro- and dinitro-BPA, suggesting that abiotic nitration between the biogenic nitrite and BPA played a major role in the transformation of BPA in the batch AOB system. Nitrite concentrations, temperature, and pH values were the major factors to influence the reaction rate. Furthermore, the yeast estrogenic screening assay showed that the formed nitro- and dinitro-BPA had much less estrogenic activity as compared with its parent compound BPA. Similar reactions of abiotic nitration were considered for 4-n-nonylphenol (nNP) and 4-n-octylphenol (nOP) since nitro-nNP and nitro-nOP were detected by UPLC-Q-TOF MS. In addition, results from the local wastewater treatment plant (WWTP) showed the occurrence of nitro-BPA and dinitro-BPA during the biological treatment process and in the effluent, indicating that nitration of BPA is also a pathway for removal of BPA. Results of this study provided implication that AOB in the WWTPs might contribute to removal of selected endocrine-disrupting compounds (EDCs) through abiotic nitritation.

Rapid debromination of tetrabromobisphenol A by Cu/Fe bimetallic nanoparticles in water, its mechanisms, and genotoxicity after treatments.

Tetrabromobisphenol A (TBBPA), a widely used brominated flame retardants, has been detected in various environmental matrices and is known to cause various adverse effects on human bodies. This study examined the feasibility and effectiveness of remediating TBBPA using Cu/Fe bimetallic nanoparticles (Cu/Fe BNPs) at various environmental and operational conditions. In general, TBBPA removal rate and debromination efficiency increased with higher Cu doping, higher Cu/Fe BNPs loading, higher temperature, and lower pH. At optimal conditions, TBBPA was completed removed at a rate constant > 0.2 min-1 where over 90% TBBPA was transformed to BPA within 30 min. The activation energy was found to be 35.6 kJ/mol, indicating that TBBPA was predominantly removed via surface-controlled reactions. Under pH 3-7 and ≥ 25 °C, debromination was the dominant removal mechanism compared to adsorption. The complete debromination pathway and the time-evolution of intermediates byproducts at different pHs were also presented. Cu/Fe BNPs can be reused for more than 6 times with performance constancy. Genotoxic tests showed that the treated solution did not find a significant hazardous potential. The byproducts can be further degraded by additional H2O2 through Fenton reaction. These results demonstrated the efficacy of Cu/Fe BNPs for treating TBBPA and its potential for degrading other halogenated organic compounds.

Revisiting of persistent organic pollution occurrence and distribution in the surface sediment along western Taiwan coast.

Levels of persistent organic pollutants (POPs), including PAHs, PCBs, DDTs, and PBDEs, were measured in sediment collected from along the Taiwan coast and compared to previous studies. The dominant POPs were PAHs, followed by PCBs, PBDEs, and DDTs. The highest levels of PAHs and PCBs were found in sediment from harbors in southern Taiwan, which are surrounded by densely populated areas and affected by multiple industrial activities. In contrast, significantly higher levels of PBDEs were found at the northern coastline, which has a higher population and includes the metropolitan Taipei area. Using diagnostic PAH ratios, the predominant sources of PAHs in coastal Taiwan was determined to be pyrolytic-related activities. The main component of each POP was low- to moderately-chlorinated congeners, p,p'-DDE and BDE209, respectively. Further studies are required to assess the impact of these POPs on marine and coastal ecosystem.

DNA modifications by the omega-3 lipid peroxidation-derived mutagen 4-oxo-2-hexenal in vitro and their analysis in mouse and human DNA.

4-Oxo-2-hexenal (4-OHE), which forms a 2'-deoxyguanosine (dG) adduct in a model lipid peroxidation system, is mutagenic in the Ames test. It is generated by the oxidation of omega-3 fatty acids and is commonly found in dietary fats, such as fish oil, perilla oil, rapeseed oil, and soybean oil. 4-OHE also forms adducts with 2'-deoxyadenosine (dA), 2'-deoxycytidine (dC), and 5-methyl-2'-deoxycytidine (5-Me-dC) in DNA. In this study, we characterized the structures of these adducts in detail. We measured the amounts of 4-OHE-DNA adducts in mouse organs by LC/MS/MS, after 4-OHE was orally administered to mice. The 4-OHE-dA, 4-OHE-dC, 4-OHE-dG, and 4-OHE-5-Me-dC adducts were detected in stomach and intestinal DNA in the range of 0.25-43.71/10(8) bases. After the 4-OHE administration, the amounts of these DNA adducts decreased gradually over 7 days. We also detected 4-OHE-dC in human lung DNA, in the range of 2.6-5.9/10(9) bases. No difference in the 4-OHE adduct levels was detected between smokers and nonsmokers. Our results suggest that 4-OHE-DNA adducts are formed by endogenous as well as environmental lipid peroxides.

Detection of lipid peroxidation-induced DNA adducts caused by 4-oxo-2(E)-nonenal and 4-oxo-2(E)-hexenal in human autopsy tissues.

DNA adducts are produced both exogenously and endogenously via exposure to various DNA-damaging agents. Two lipid peroxidation (LPO) products, 4-oxo-2(E)-nonenal (4-ONE) and 4-oxo-2(E)-hexenal (4-OHE), induce substituted etheno-DNA adducts in cells and chemically treated animals, but the adduct levels in humans have never been reported. It is important to investigate the occurrence of 4-ONE- and 4-OHE-derived DNA adducts in humans to further understand their potential impact on human health. In this study, we conducted DNA adductome analysis of several human specimens of pulmonary DNA as well as various LPO-induced DNA adducts in 68 human autopsy tissues, including colon, heart, kidney, liver, lung, pancreas, small intestine, and spleen, by liquid chromatography tandem mass spectrometry. In the adductome analysis, DNA adducts derived from 4-ONE and 4-OHE, namely, heptanone-etheno-2'-deoxycytidine (HεdC), heptanone-etheno-2'-deoxyadenosine (HεdA), and butanone-etheno-2'-deoxycytidine (BεdC), were identified as major adducts in one human pulmonary DNA. Quantitative analysis revealed 4-ONE-derived HεdC, HεdA, and heptanone-etheno-2'-deoxyguanosine (HεdG) to be ubiquitous in various human tissues at median values of 10, 15, and 8.6 adducts per 10(8) bases, respectively. More importantly, an extremely high level (more than 100 per 10(8) bases) of these DNA adducts was observed in several cases. The level of 4-OHE-derived BεdC was highly correlated with that of HεdC (R(2) = 0.94), although BεdC was present at about a 7-fold lower concentration than HεdC. These results suggest that 4-ONE- and 4-OHE-derived DNA adducts are likely to be significant DNA adducts in human tissues, with potential for deleterious effects on human health.

In vitro and in vivo screening for environmentally friendly benzophenone-type UV filters with beneficial tyrosinase inhibition activity.

Benzophenones (BPs) are a group of chemically similar organic compounds commonly used in formulations of sunscreen and other personal care products as UV filters to protect our skin against sunlight overexposure. Studies have shown that the occurrence of certain BPs (e.g., BP-3 and its metabolite BP-1) in multiple environmental matrices may increase the incidence of coral planulae bleaching and estrogenic effects on aquatic life. Currently, most BPs are not yet comprehensively screened in vitro and in vivo for their ecotoxicity under environmentally relevant concentrations. This study systematically assessed the in vitro and in vivo toxicity and activity of the 7 most commonly used BPs (BP-1, BP-2, BP-3, BP-4, BP-6, BP-7 and BP-8) to select BP alternatives with lower ecotoxicity and extra beneficial functions. BP-2 (LC50 = 18.43 µM) was least toxic and BP-3 (LC50 = 4.10 µM) and BP-8 (LC50 =1.62 µM) were less and most toxic, respectively, in terms of 96-hr acute mortality of medaka larvae. BP-2 at environmentally relevant concentrations (5-50 nM) did not significantly alter locomotion and oxidative stress responses of medaka larvae from 24-hr to 7-day exposure, whereas BP-3 and BP-8 at 5 nM induced hypoactivity or changed fish swimming angles. Only BP-2 was able to inhibit in vitro mushroom tyrosinase activity, with EC50 value 19.7 µM. Also, BP-2 could effectively suppress melanin formation and tyrosinase activity in zebrafish embryos. Among the 7 tested BPs, BP-2 was the least toxic and the most environmentally friendly UV filter with extra benefit for tyrosinase inhibition and could be a promising alternative to the use of toxic BPs.

Biodegradation of the endocrine disrupter 4-t-octylphenol by the non-ligninolytic fungus Fusarium falciforme RRK20: Process optimization, estrogenicity assessment, metabolite identification and proposed pathways.

4-t-octylphenol (4-t-OP), a well-known endocrine disrupting compound, is frequently found in various environmental compartments at levels that may cause adverse effects to the ecosystem and public health. To date, most of the studies that investigate microbial transformations of 4-t-OP have focused on the process mediated by bacteria, ligninolytic fungi, or microbial consortia. There is no report on the complete degradation mechanism of 4-t-OP by non-ligninolytic fungi. In this study, we conducted laboratory experiments to explore and characterize the non-ligninolytic fungal strain Fusarium falciforme RRK20 to degrade 4-t-OP. Using the response surface methodology, the initial biomass concentration and temperature were the factors identified to be more influential on the efficiency of the biodegradation process as compared with pH. Under the optimized conditions (i.e., 28 °C, pH 6.5 with an initial inoculum density of 0.6 g L-1), 25 mg L-1 4-t-OP served as sole carbon source was completely depleted within a 14-d incubation; addition of low dosage of glucose was shown to significantly accelerate 4-t-OP degradation. The yeast estrogenic screening assay further confirmed the loss of estrogenic activity during the biodegradation process, though a longer incubation period was required for complete removal of estrogenicity. Metabolites identified by LC-MS/MS revealed that strain RRK20 might degrade 4-t-OP as sole energy source via alkyl chain oxidation and aromatic ring hydroxylation pathways. Together, these results not only suggest the potential use of non-ligninolytic fungi like strain RRK20 in remediation of 4-t-OP contaminated environments but may also improve our understanding of the environmental fate of 4-t-OP.

Assessing the endocrine disrupting potentials and genotoxicity in environmental samples from Taiwanese rivers.

BACKGROUND: Surface waters receive a variety of organic pollutants via wastewater discharge, and sediment represents a sink for hydrophobic contaminants. In this study, we used in vitro yeast-based reporter gene assays and a Bacillus subtilis Rec-assay to examine the occurrence of endocrine disrupting activities and genotoxic potentials in samples collected from three Taiwanese rivers. Levels of 51 polycyclic aromatic hydrocarbons (PAHs) in muscles of fish captured from same rivers were also analyzed to assess in vivo pollution of PAHs. RESULTS: Antagonist activities for androgen receptor and retinoid X receptor (RXR) were detected in river water extracts at environmentally relevant concentrations., and sediment extracts exhibited RXR agonist, RXR antagonist, and genotoxic potentials concurrently. Σ16 PAHs in fish muscles ranged from 44.9-242.4 ng g- 1 dry weight, representing 38 to 59% of the total 51 PAHs concentrations, and methylated PAHs of low molecular weight PAHs were often detected as well. CONCLUSION: Taiwanese river sediment samples concomitantly exhibited RXR disrupting potentials and genotoxic activities, whereas RXR agonist and antagonist activities were simultaneously detected in several dry-season sediment extracts. PAH levels in fish muscles were categorized as minimally polluted by aromatic compounds, nonetheless, the presence of methylated PAHs in muscles samples may be of concern owing to the higher toxic potentials than their parent compounds.

Oxidative DNA damage in XPC-knockout and its wild mice treated with equine estrogen.

Long-term hormone replacement therapy with equine estrogens is associated with a higher risk of breast, ovarian, and endometrial cancers. Reactive oxygen species generated through redox cycling of equine estrogen metabolites may damage cellular DNA. Such oxidative stress may be linked to the development of cancers in reproductive organs. Xeroderma pigmentosa complementation group C-knockout ( Xpc-KO) and wild-type mice were treated with equilenin (EN), and the formation of 7,8-dihydro-8-oxodeoxyguanosine (8-oxodG) was determined as a marker of typical oxidative DNA damage, using liquid chromatography electrospray tandem mass spectrometry. The level of hepatic 8-oxodG in wild-type mice treated with EN (5 or 50 mg/kg/day) was significantly increased by approximately 220% after 1 week, as compared with mice treated with vehicle. In the uterus also, the level of 8-oxodG was significantly increased by more than 150% after 2 weeks. Similar results were observed with Xpc-KO mice, indicating that Xpc does not significantly contribute to the repair of oxidative damage. Oxidative DNA damage generated by equine estrogens may be involved in equine estrogen carcinogenesis.

7-ketocholesterol and 27-hydroxycholesterol decreased doxorubicin sensitivity in breast cancer cells: estrogenic activity and mTOR pathway.

Hypercholesterolemia is one of the risk factors for poor outcome in breast cancer therapy. To elucidate the influence of the main circulating oxysterols, cholesterol oxidation products, on the cell-killing effect of doxorubicin, cells were exposed to oxysterols at a subtoxic concentration. When cells were exposed to oxysterols in fetal bovine serum-supplemented medium, 7-ketocholesterol (7-KC), but not 27-hydroxycholesterol (27-HC), decreased the cytotoxicity of doxorubicin in MCF-7 (high estrogen receptor (ER)α/ERß ratio) cells and the decreased cytotoxicity was restored by the P-glycoprotein inhibitor verapamil. 7-KC stimulated the efflux function of P-glycoprotein and reduced intracellular doxorubicin accumulation in MCF-7 but not in ERα(-) MDA-MB-231 and the resistant MCF-7/ADR cells. In MCF-7 cells, 7-KC increased the mRNA and protein levels of P-glycoprotein. The 7-KC-suppressed doxorubicin accumulation was restored by the fluvestrant and ERα knockdown. In a yeast reporter assay, the ERα activation by 7-KC was more potent than 27-HC. 7-KC, but not 27-HC, stimulated the expression of an ER target, Trefoil factor 1 in MCF-7 cells. When charcoal-stripped fetal bovine serum was used, both 7-KC and 27-HC induced Trefoil factor 1 expression and reduced doxorubicin accumulation in MCF-7 cells. 7-KC-reduced doxorubicin accumulation could be reversed by inhibitors of phosphatidylinositol 3-kinase, Akt, and mammalian target of rapamycin (mTOR). These findings demonstrate that 7-KC decreases the cytotoxicity of doxorubicin through the up-regulation of P-glycoprotein in an ERα- and mTOR-dependent pathway. The 7-KC- and 27-HC-elicited estrogenic effects are crucial in the P-glycoprotein induction in breast cancer cells.

Detection of endocrine active substances in the aquatic environment in southern Taiwan using bioassays and LC-MS/MS.

Endocrine active substances, including naturally occurring hormones and various synthetic chemicals have received much concern owing to their endocrine disrupting potencies. It is essential to monitor their environmental occurrence since these compounds may pose potential threats to biota and human health. In this study, yeast-based reporter assays were carried out to investigate the presence of (anti-)androgenic, (anti-)estrogenic, and (anti-)thyroid compounds in the aquatic environment in southern Taiwan. Liquid chromatography tandem mass spectrometry (LC-MS/MS) was also used to measure the environmental concentrations of selected endocrine active substances for assessing potential ecological risks and characterizing contributions to the endocrine disrupting activities. Bioassay results showed that anti-androgenic (ND-7489 µg L(-1) flutamide equivalent), estrogenic (ND-347 ng L(-1) 17ß-estradiol equivalent), and anti-thyroid activities were detected in the dissolved and particulate phases of river water samples, while anti-estrogenic activities (ND-10 µg L(-1) 4-hydroxytamoxifen equivalent) were less often found. LC-MS/MS analysis revealed that anti-androgenic and estrogenic contaminants, such as bisphenol A, triclosan, and estrone were frequently detected in Taiwanese rivers. In addition, their risk quotient values were often higher than 1, suggesting that they may pose an ecological risk to the aquatic biota. Further identification of unknown anti-androgenic and estrogenic contaminants in Taiwanese rivers may be necessary to protect Taiwan's aquatic environment.

Application of a multiwalled carbon nanotube-chitosan composite as an electrode in the electrosorption process for water purification.

In this study, a multiwalled carbon nanotubes-chitosan (CNTs-CS) composite electrode was fabricated to enable water purification by electrosorption. The CNTs-CS composite electrode was shown to possess excellent capacitive behaviors and good pore accessibility by electrochemical impedance spectroscopy, galvanostatic charge-discharge, and cyclic voltammetry measurements in 1 M H2SO4 electrolyte. Moreover, the CNTs-CS composite electrode showed promising performance for capacitive water desalination. At an electric potential of 1.2 V, the electrosorption capacity and electrosorption rate of NaCl ions on the CNTs-CS composite electrode were determined to be 10.7 mg g(-1) and 0.051 min(-1), respectively, which were considerably higher than those of conventional activated electrodes. The improved electrosorption performance could be ascribed to the existence of mesopores. Additionally, the feasibility of electrosorptive removal of aniline from an aqueous solution has been demonstrated. Upon polarization at 0.6 V, the CNTs-CS composite electrode had a larger electrosorption capacity of 26.4 mg g(-1) and a higher electrosorption rate of 0.006 min(-1) for aniline compared with the open circuit condition. The enhanced adsorption resulted from the improved affinity between aniline and the electrode under electrochemical assistance involving a nonfaradic process. Consequently, the CNT-CS composite electrode, exhibiting typical double-layer capacitor behavior and a sufficient potential range, can be a potential electrode material for application in the electrosorption process.

Exploring potential contributors to endocrine disrupting activities in Taiwan's surface waters using yeast assays and chemical analysis.

Surface waters serve as sinks for anthropogenic contaminants, including naturally occurring hormones and a variety of synthetic endocrine active substances. To investigate the presence of endocrine active contaminants in the aquatic environment in Taiwan, river water and suspended solids were analyzed by yeast assays to examine the distribution of estrogenic, androgenic, and aryl hydrocarbon receptor agonist activities. The results showed that dry-season river samples exhibited strong estrogenic and aryl hydrocarbon receptor agonist activities, but no androgenic activity was detected. Owing to the ubiquitous detection of estrogenic activities in Taiwan's surface waters, samples were further subjected to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis for quantification of selected estrogenic compounds. LC-MS/MS results indicated that natural estrogens, such as estrone and 17ß-estradiol were often the most contributing compounds for the bioassay-derived estrogenic activities due to their strong estrogenic potencies and high detection frequencies, whereas high concentrations of bisphenol A and nonylphenol also posed a threat to the aquatic ecosystems in Taiwan. Water samples eliciting strong estrogenic activities were further fractionated using high performance liquid chromatography, and significant estrogenic activities were detected in fractions containing estrone, 17ß-estradiol, 17α-ethynylestradiol, and bisphenol A. Also, the presence of unidentified estrogenic compounds was found in few river water samples. Further identification of unknown endocrine active substances is necessary to better protect the aquatic environment in Taiwan.

Clinical implications of species identification in monomicrobial Aeromonas bacteremia.

BACKGROUND: Advances in Aeromonas taxonomy have led to the reclassification of aeromonads. Hereon, we aimed to re-evaluate the characteristics of Aeromonas bacteremia, including those of a novel species, Aeromonas dhakensis. METHODOLOGY/PRINCIPAL FINDINGS: A retrospective study of monomicrobial Aeromonas bacteremia at a medical center in southern Taiwan from 2004-2011 was conducted. Species identification was based on rpoB sequencing. Of bacteremia of 153 eligible patients, A. veronii (50 isolates, 32.7%), A. dhakensis (48, 31.4%), A. caviae (43, 28.1%), and A. hydrophila (10, 6.5%) were the principal causative species. A. dhakensis and A. veronii bacteremia were mainly community-acquired and presented as primary bacteremia, spontaneous bacterial peritonitis, or skin and soft-tissue infection, whereas A. caviae was associated with hospital-onset bacteremia. The distribution of the AmpC ß-lactamase and metallo-ß-lactamase genes was species-specific: bla(AQU-1), bla(MOX), or bla(CepH) was present in A. dhakensis, A. caviae, or A. hydrophila, respectively, and bla(CphA) was present in A. veronii, A. dhakensis, and A. hydrophila. The cefotaxime resistance rates of the A. caviae, A. dhakensis, and A. hydrophila isolates were higher than that of A. veronii (39.5%%, 25.0%, and 30% vs. 2%, respectively). A. dhakensis bacteremia was linked to the highest 14-day sepsis-related mortality rate, followed by A. hydrophila, A. veronii, and A. caviae bacteremia (25.5%, 22.2%, 14.0%, and 4.7%, respectively; P = 0.048). Multivariate analysis revealed that A. dhakensis bacteremia, active malignancies, and a Pitt bacteremia score ≥ 4 was an independent mortality risk factor. CONCLUSIONS/SIGNIFICANCE: Characteristics of Aeromonas bacteremia vary between species. A. dhakensis prevalence and its associated poor outcomes suggest it an important human pathogen.

Occurrence of xenobiotic ligands for retinoid X receptors and thyroid hormone receptors in the aquatic environment of Taiwan.

Various synthetic compounds are frequently discharged into the environment via human activities. Among them, certain contaminants may disrupt normal physiological functions of wildlife and humans via interactions with nuclear receptors. To protect human health and the environment, it is important to detect environmental ligands for human nuclear receptors. In this study, yeast-based reporter gene assays were used to investigate the occurrence of xenobiotic ligands for retinoid X receptors (RXR) and thyroid hormone receptors (TR) in the aquatic environment of Taiwan. Experimental results revealed that RXR agonist/antagonist activity was detected in river water and sediment samples. In particular, high RXR agonist/antagonist activity was found in the samples collected near river mouths. Additionally, few samples also elicited significant TR antagonist activity. Our findings show that the aquatic environment of Taiwan was contaminated with RXR and TR ligands. Further study is necessary to identify these xenobiotic RXR and TR agonists and antagonists.

Monitoring of xenobiotic ligands for human estrogen receptor and aryl hydrocarbon receptor in industrial wastewater effluents.

Industrial wastewater contains a variety of toxic substances, which may severely contaminate the aquatic environment if discharged without adequate treatment. In this study, effluents from a thin film transistor liquid crystal display wastewater treatment plant and the receiving water were analyzed by bioassays and liquid chromatography-tandem mass spectrometry to investigate the presence of estrogenic compounds, aryl hydrocarbon receptor (AhR) agonists, and genotoxicants. Xenobiotic AhR agonists were frequently detected and, in particular, strong AhR agonist activity and genotoxicity were found in the suspended solids of the aeration tank outflow. The high AhR agonist activity in the final effluent (FE) and the downstream river water suggested that the treatment plant failed to remove the wastewater-related AhR agonists. In contrast, although significant estrogenic potency could be detected in raw wastewater or effluents from different treatment processes, the FE and the receiving river water exhibited no or weak estrogenicity. Instrumental analysis showed that bisphenol A was often detected in water samples. However, the investigated estrogenic compounds could only account for a small portion of the estrogenicity in the collected samples. Therefore, further investigation is necessary to identify the major estrogenic compounds and AhR agonist contaminants in the wastewater effluents.