Tetrabromobisphenol A (TBBPA) is a high-production chemical widely used in printed circuit boards and other polymeric materials for inflaming. As an environmental pollutant, it is widely found in various abiotic and biological media. Usually, the TBBPA could enter the body through skin contact, respiratory exposure and the dietary intake, among which respiratory exposure may be a most important exposure route. Previous studies reported that TBBPA possesses the endocrine, liver and kidney toxicity. However, few studies focused on the effects of TBBPA on respiratory toxicity. Therefore, it is urgent to study the toxic effects of TBBPA on respiratory system. In this study, human bronchial cells Beas2B and pulmonary epithelial cells 16HBE were used as subjects to study the exposure toxicity of TBBPA. Firstly, the viability and permeability of cells were assayed during the TBBPA exposure process. When TBBPA was in low concentration range (0−0.4 μmol/L), 24 h of exposure cannot significantly affect cell viability. When concentration of TBBPA was greater than 10 μmol/L, the inhibitory effect on cell activity was obviously observed. When concentration of TBBPA was up to 50 μmol/L, the cell viabilities of 16HBE and Beas2B cells decreased to 80.9% and 86.2%. It is worth noting that, as compared with bronchial epithelial cell 16HBE, lung epithelial cell Beas2B has a higher tolerance to TBBPA, which may be due to the different cell structures. In addition, the oxidation stress of cells was also determined by assaying the cell intracellular reactive oxygen species (ROSs), antioxidant enzymatic activity of superoxide dismutase (SOD) and catalase (CAT) during the whole expose duration. The results showed that the levels of intracellular ROSs obviously increased in both cells, indicating that peroxidation occurred in the cells during TBBPA exposure. Correspondingly, the enzymatic activities of SOD and CAT also increased, indicating that oxidative stress happened in cells. After that, flow cytometry was applied to analyze cell apoptosis. The results showed that partial apoptosis occurred after 24 h of TBBPA exposure, indicating that TBBPA could induce cell apoptosis. Besides, with the increase of exposure concentration, the apoptosis rate of the two kinds of cells also increased. Furthermore, the q-PCR was used to determine the apoptosis-related gene expression. The results revealed that the expression levels of apoptosis-related genes p53, Survivin , bax , bcl-2 , caspase-3 , caspase-9 were all up-regulated to different degrees, further confirming that cells were apoptotic caused by TBBPA. Further, compared with the 12-h exposure data, 24-h exposure would stimulate more intense expression up-regulation. In all, this research mainly investigated the toxicity of typical generation bromide flame retardants TBBPA on human bronchial epithelial cells 16 HBE and lung epithelial cells Beas2B. Results showed that the exposure of TBBPA could cause damage to cell viability and elicit oxidative stress in cells, which could further induce cell apoptosis. The results of cytotoxicity related to human respiratory system in this work can provide a scientific basis for revealing the health risk of toxic organic pollutants to human respiratory system.
Objective To investigate the distribution of pathogenic bacteria in the bile and blood samples of patients with obstructive jaundice.Methods A total of 322 patients with obstructive jaundice who were admitted to Department of Gastroenterology and Department of Hepatobiliary Surgery in The Affiliated Hospital of Binzhou Medical University from January 2012 to April 2016 were enrolled.Bile samples were obtained from all patients and blood culture was performed for 84 patients.The influence of benign and malignant obstruction and therapies on the detection rate of pathogenic bacteria in bile was analyzed,and the detection rate of pathogenic bacteria in bile and blood was compared.The chi- square test was used for comparison of categorical data between groups.Results Pathogenic bacteria were detected in246 patients( 246 /322),resulting in a detection rate of 76.40%.A total of 267 strains were detected,which consisted of 208 strains of Gram- negative bacteria,48 strains of Gram- positive bacteria,and 11 strains of fungi.Among the 256 patients who underwent endoscopic retrograde cholangiopancreatography( ERCP),199 were detected to have pathogenic bacteria,resulting in a detection rate of 77.73%;among the 66 patients who underwent surgery,47 were detected to have pathogenic bacteria,resulting in a detection rate of 71.21%.There was no significant difference in the detection rate of pathogenic bacteria between these two groups( χ~2= 1.238,P = 0.266).Among the 288 patients with benign obstructive jaundice,215 were detected to have pathogenic bacteria,resulting in a detection rate of 74.65%;among the34 patients with malignant obstructive jaundice,31 were detected to have pathogenic bacteria,resulting in a detection rate of 91.18%.There was a significant difference in the detection rate of pathogenic bacteria between these two groups( χ~2= 4.605,P = 0.032),and there was a significant difference in the distribution of pathogenic bacteria in bile between these two groups( χ~2= 0.159,P = 0.690).The types of pathogenic bacteria in bile samples were similar to those in blood samples,and there was a significant difference in the detection of pathogenic bacteria between them( χ~2= 13.235,P < 0.001).Conclusion There is no significant difference in the detection rate of pathogenic bacteria determined by ERCP or surgery in patients with obstructive jaundice.For patients who cannot undergo ERCP or surgery,blood culture results can be used to guide clinical medication.
Due to the specific action on bacterial cell wall, β-lactam antibiotics have gained widespread usage as they exhibit a high degree of specificity in targeting bacteria, but causing minimal toxicity to host cells. Under antibiotic pressure, bacteria may opt to shed their cell walls and transform into L-form state as a means to evade the antibiotic effects. In this study, we explored and identified diverse optimal conditions for both Gram-negative bacteria (E. coli DH5α (CTX)) and Gram-positive bacteria (B. subtilis ATCC6633), which were induced to L-form bacteria using lysozyme (0.5 ppm) and meropenem (64 ppm). Notably, when bacteria transformed into L-form state, both bacterial strains showed varying degrees of increased resistance to antibiotics polymyxin E (PE), meropenem, rifampicin, and tetracycline (TET). E. coli DH5α (CTX) exhibited the most significant enhancement in resistance to TET, with a 128-fold increase, while B. subtilis ATCC6633 showed a 32-fold increase in resistance to TET and PE. Furthermore, L-form bacteria maintained their normal metabolic activity, combined with enhanced oxidative stress, served as an adaptive strategy promoting the sustained survival of L-form bacteria. This study provided a theoretical basis for comprehending antibiotic resistance mechanisms, developing innovative treatment strategies, and confronting global antibiotic resistance challenges.
With the rapid growth of aquaculture globally, large amounts of antibiotics have been used to treat aquatic disease, which may accelerate induction and spread of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in aquaculture environments. Herein, metagenomic and 16S rRNA analyses were used to analyze the potentials and co-occurrence patterns of pathogenome (culturable and unculturable pathogens), antibiotic resistome (ARGs), and mobilome (mobile genetic elements (MGEs)) from mariculture waters near 5000 km coast of South China. Total 207 species of pathogens were identified, with only 10 culturable species. Furthermore, more pathogen species were detected in mariculture waters than those in coastal waters, and mariculture waters were prone to become reservoirs of unculturable pathogens. In addition, 913 subtypes of 21 ARG types were also identified, with multidrug resistance genes as the majority. MGEs including plasmids, integrons, transposons, and insertion sequences were abundantly present in mariculture waters. The co-occurrence network pattern between pathogenome, antibiotic resistome, and mobilome suggested that most of pathogens may be potential multidrug resistant hosts, possibly due to high frequency of horizontal gene transfer. These findings increase our understanding of mariculture waters as reservoirs of antibiotic resistome and mobilome, and as yet another hotbed for creation and transfer of new antibiotic-resistant pathogenome.
The emergence of antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) in the environment has created obstacles when treating infectious diseases with antibiotics. Wastewater treatment plants (WWTPs) serve as reservoirs for ARB and ARGs and can disseminate them into the environment. It is important to understand and address these risks. Generally, professional disinfection processes have been used in WWTPs to disinfect the target water body, with the goal of eliminating pathogenic microorganisms in the water. However, ARGs are not generally considered, and antibiotic resistance has spread and developed through horizontal gene transfer (HGT). This Review provides a detailed overview of the application progress of different traditional and new disinfection technologies in removing ARB and ARGs, mainly focusing on the bacterial inactivation mechanisms of chlorination, ozonation, ultraviolet (UV) (including UVA, UVB, and UVC), sunlight, sunlight-dissolved organic matter (DOM), and photocatalysis (PC)/photoelectrocatalysis (PEC). In addition, this Review also focuses on the disinfection technology involved in the transfer of ARGs and clarifies the underlying transfer mechanisms in water environments. Furthermore, by linking the mechanisms of bacterial inactivation, the Review describes how SOS response and cell membrane permeability may be the key step in the conjugation, transformation, and transduction of ARGs. Finally, given the applications and current problems associated with traditional water disinfection technologies and light-based disinfection technologies in removing and controlling ARB and ARGs, this Review describes the current challenges and opportunities to facilitate the development of future disinfection technologies. The Review also highlights future research directions related to ARG transmission control.
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