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Background: The dissemination of antibiotic resistance genes (ARGs) poses a substantial threat to environmental safety and human health. Herein, we present a longitudinal paired study across the swine lifetime from birth to market, coupled with metagenomic sequencing to explore the dynamics of ARGs and their health risk in the swine fecal microbiome. Results: We systematically characterized the composition and distribution of ARGs among the different growth stages. In total, 829 ARG subtypes belonging to 21 different ARG types were detected, in which tetracycline, aminoglycoside, and MLS were the most abundant types. Indeed, 134 core ARG subtypes were shared in all stages and displayed a growth stage-associated pattern. Furthermore, the correlation between ARGs, gut microbiota and mobile genetic elements (MGEs) revealed Escherichia coli represented the main carrier of ARGs. We also found that in most cases, the dominant ARGs could be transmitted to progeny piglets, suggesting the potential ARGs generation transmission. Finally, the evaluation of the antibiotic resistance threats provides us some early warning of those high health risk ARGs. Conclusions: Collectively, this relatively more comprehensive study provides a primary overview of ARG profile in swine microbiome across the lifetime and highlights the health risk and the intergenerational spread of ARGs in pig farm. [ABSTRACT FROM AUTHOR]

Chlorine disinfectants have been widely used in the poultry supply chain but this exposure can also result in the development of bacterial tolerance to chlorine and this is often linked to antibiotic cross-resistance. The objectives of this study were to investigate sodium hypochlorite (NaClO) tolerance of Salmonella isolated from poultry supply chains and evaluate cross-resistance. We collected 172 Salmonella isolates from poultry farms, slaughter houses and retail markets in China during 2019–2020. We found that S. Enteritidis, S. Kentucky, and S. Typhimurium constituted > 80% of our Salmonella isolates. Overall, 68% of Salmonella isolates were resistant to > 3 antibiotics and S. Kentucky displayed a significantly (p > 0.05) higher frequency (93.2%) of multidrug resistance than the other serovars. Tolerance to chlorine at MIC > 256 mg/L was detected in 93.6% of isolates (161/172) and tolerant isolates displayed higher decimal reduction times (D value) and less ultrastructural damage than did the suspectable strains under chlorine stress. Spearman analysis indicated significant positive correlations between chlorine tolerance (evaluated by the OD method) and antibiotic resistance (p < 0.05) to ceftiofur, tetracycline, ciprofloxacin and florfenicol and this was most likely due to efflux pump over-expression. The most frequently detected chlorine resistance gene was qacE Δ 1 (83.1%, n = 143) and we found a positive correlation between its presence and MIC levels (r = 0.66, p < 0.0001). Besides, we found weak correlations between chlorine-tolerance and antibiotic resistance genes. Our study indicated that chlorine disinfectants most likely played an important role in the emergence of chlorine tolerance and spread of antibiotic resistance and therefore does not completely control the risk of food-borne disease. The issue of disinfectant resistance should be examined in more detail at the level of the poultry production chain. [ABSTRACT FROM AUTHOR]

In this work, the occurrence of 34 common antibiotic (15 sulfonamides and 19 quinolones) residues were evaluated in 236 ready‐to‐eat duck eggs (salted and preserved duck eggs) marketed through e‐commerce stores by ultra‐performance liquid chromatography coupled to tandem mass spectrometry, and subsequent dietary risk assessments for Chinese consumers were conducted. Among violated positives in duck egg samples, 11 analytes were found including sulfamethazine, sulfaquinoxaline, sulfamethoxazole, sulfadiazine, sulfamonomethoxine, ciprofloxacin, enrofloxacin, ofloxacin, flumequine, sarafloxacin, and nalidixic acid. A higher number of antibiotics were detected in salted duck eggs (five sulfonamides and six quinolones) than in preserved duck eggs (one sulfonamide and two quinolones). The maximum contamination of sulfonamides and quniolones was 448.0 µg/kg (sulfaquinoxaline) and 563.7 µg/kg (enrofloxacin) in salted duck eggs, respectively. Dietary exposure was evaluated through the estimated daily intake (EDI) of risky antibiotics (sulfamethazine, ciprofloxacin, and enrofloxacin) and hazard quotients (HQs). The results showed that EDIs and HQs were in the range of 0.0004 to 0.0099 µg/kg bw/day and 0.0009 to 0.1594%, respectively. The risk was low since HQs obtained were less than 100%. However, a special attention should be paid to ready‐to‐eat duck egg products high percentile consumers with the prosperity of e‐commerce market in China. Practical Application: The present analytical method could be used for multiresidue determination of antibiotics in ready‐to‐eat duck eggs, and dietary risk assessments of risky antibiotics provided a support for the work of regulatory bodies to conduct surveillance programs regarding food safety evaluation of ready‐to‐eat foods. [ABSTRACT FROM AUTHOR]

Antimicrobial growth promoters (AGPs) are commonly used in the livestock industry at subtherapeutic levels to improve production efficiency, which is achieved mainly through modulation of the intestinal microbiota. However, how different classes of AGPs, particularly ionophores, regulate the gut microbiota remains unclear. In this study, male Cobb broiler chickens were supplemented for 14 days with or without one of five commonly used AGPs including three classical antibiotics (bacitracin methylene disalicylate, tylosin, and virginiamycin) and two ionophores (monensin and salinomycin) that differ in antimicrobial spectrum and mechanisms. Deep sequencing of the V3-V4 region of the bacterial 16S rRNA gene revealed that two ionophores drastically reduced a number of rare bacteria resulting in a significant decrease in richness and a concomitant increase in evenness of the cecal microbiota, whereas three antibiotics had no obvious impact. Although each AGP modulated the gut microbiota differently, the closer the antibacterial spectrum of AGPs, the more similarly the microbiota was regulated. Importantly, all AGPs had a strong tendency to enrich butyrate- and lactic acid-producing bacteria, while reducing bile salt hydrolase-producing bacteria, suggestive of enhanced metabolism and utilization of dietary carbohydrates and lipids and improved energy harvest, which may collectively be responsible for the growth-promoting effect of AGPs. [ABSTRACT FROM AUTHOR]

Photocatalysis degradation of tetracycline hydrochloride with high concentration over a hollow microsphere S-doped g-C 3 N 4. [Display omitted] For the past few years, graphitic carbon nitride (g-C 3 N 4) has been widely used to eliminate environmental pollutants, but limited active site on surface and low separation/migration ability suppress its practical uses. Herein, we adopted a supramolecular self-assembly route followed with S doping to synthesize S-doped g-C 3 N 4 with a hollow microsphere composition (SCNHM), where the shell was demonstrated to compose of ultrathin nanosheets. The unique structural characteristics endow the SCNHM with high specific surface area (∼81 m2 g−1) to provide abundant reaction sites and enhanced light-harvesting due to the light-scattering effect of hollow structure. Moreover, the S dopant meliorated the electronic structure to narrow the bandgap and promoted the charge separation/transfer capability. With this synergistic effect, the SCNHM presented greatly improved photocatalytic activity for degrading tetracycline hydrochloride (TC) compared to the CN, SCN and CNHM samples. This photocatalyst could eliminate high-concentration TC (50 mg L−1) in 18 min, and the 30 min removal efficiencies of 100 mg L−1 and 200 mg L−1 reached 92 % and 60 %, which is much better than the reported photocatalysts in literatures (usually ≤ 20 mg L−1). Additionally, the good photocatalytic durability was confirmed and the degradation pathway of TC was proposed. Furthermore, the SCNHM was proved to meanwhile possess superior performance for inactivating the typical Gram-positive bacterium of Staphylococcus aureus (S. aureus) and the typical Gram-negative bacterium of Escherichia coli (E. coli). Finally, based on determination of band alignment and detection of active species, a plausible photocatalytic mechanism was proposed. [ABSTRACT FROM AUTHOR]

Chlorine and its derivatives, such as sodium hypochlorite (NaClO) and chlorine dioxide, are frequently employed as disinfectants throughout the pork supply chain in China. Nevertheless, the extensive use of NaClO has the potential to cause the creation of 'chlorine-tolerant bacteria' and accelerate the evolution of antibiotic resistance. This study evaluated the efficacy of NaClO disinfection by examining alterations in the microbiome and resistome of a pork wholesale market (PWM), and bacteria isolation and analysis were performed to validate the findings. As expected, the taxonomic composition s of bacteria was significantly different before and after disinfection. Notably, Salmonella enterica (S. enterica) , Salmonella bongori (S. bongori), Escherichia coli (E. coli), Klebsiella pneumoniae (K. pneumoniae) , and Pseudomonas aeruginosa (P. aeruginosa) were observed on all surfaces, indicating that the application of NaClO disinfection treatment in PWM environments for pathogenic bacteria is limited. Correlations were identified between antibiotic resistance genes (ARGs) associated with aminoglycosides (aph(3′')-I, aph(6′)-I), quinolone (qnrB, abaQ), polymyxin (arnA, mcr-4) and disinfectant resistance genes (emrA/BD , mdtA/B/C/E/F). Furthermore, correlations were found between risk Rank I ARGs associated with aminoglycoside (aph(3′)-I), tetracycline (tetH), beta_lactam (TEM-171), and disinfectant resistance genes (mdtB/C/E/F, emrA, acrB, qacG). Importantly, we found that Acinetobacter and Salmonella were the main hosts of disinfectant resistance genes. The resistance mechanisms of the ARGs identified in PWM were dominated by antibiotic deactivation (38.7%), antibiotic efflux (27.2%), and antibiotic target protection (14.4%). The proportion of genes encoding efflux pumps in the PWM resistome increased after disinfection. Microbial cultures demonstrated that the traits of microbial contamination and antibiotic resistane were consistent with those observed by metagenomic sequencing. This study highlights the possibility of cross-resistance between NaClO disinfectants and antibiotics, which should not be ignored. [Display omitted] • Taxonomic compositions of bacterial were changed before and after disinfection. • The application of NaClO disinfection treatment on pathogenic bacteria was limited. • The Acinetobacter and Salmonella were main hosts of disinfectant resistance genes. • Significant correlations were found between ARGs and disinfectant resistance genes. • The proportion of genes encoding efflux pumps increased in the PMW disinfection. [ABSTRACT FROM AUTHOR]

Graphitic carbon nitride (GCN) has been demonstrated to be a potential piezocatalyst in environmental remediation. The common piezoelectric materials synthesized by GCN are often designed to have a larger specific surface area to increase the adsorption and degradation performance of environmental pollutants. However, these process will also decrease the particle size of two-dimensional GCN, which thus affect the in-plane polarization intensity and inhibit the piezoelectric catalytic performance. Herein, we proposed an NH 4 Cl assistant synthesis to obtain ultrathin Cl-doped GCN (Cl-GCN) with large surface area and developed porosity. The introduced Cl with strong electronegativity can better change the electron cloud density distribution in GCN. From the experiment measurements and the theoretical calculation, Cl dopant in GCN skeleton resulted in partially destroyed crystal symmetry, and increased the structural polarity. As a result, the Cl-GCN simultaneously possessing large surface area and high piezoelectric polarization contributed enhanced piezocatalytic activity for degradation of antibiotics compared to the pristine GCN. Within 30 min, the degradation efficiency of tetracycline hydrochloride (TC-HCl) reached to ca. 94%. Besides, the effects of antibiotic concentration as well as the piezocatalytic durability for eliminating different antibiotics were investigated. Finally, based on determinations of mainly active species and the intermediate products during the piezocatalytic process, a plausible piezocatalytic degradation mechanism was proposed. This study implies that enhancing the piezoelectric polarization of piezocatalyst by heteroatomic doping and meanwhile improving its surface area are promising strategies to promoting piezocatalytic performance both for environmental application and for clean energy production. Piezocatalytic degradation of TC-HCl over a morphologic modified GCN nanosheet. [Display omitted] • The ultrathin structure of Cl-doped GCN was conducive to piezoelectric reaction. • Destruction of crystal symmetry by Cl promoted piezoelectric polarization. • The oxidizing groups and electrochemical mechanism were determined. • The degradation route of TC-HCl by piezoelectric catalysis was proposed. [ABSTRACT FROM AUTHOR]