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The occurrence, distribution, and ecological risk assessment of 36 antibiotics from five groups, including macrolides (MLs), fluoroquinolones (FQs), tetracyclines (TCs), amphenicols (APs), and sulfonamides (SAs), were investigated for the first time in the Anning River, Sichuan Province, China. The results show that antibiotics were widely present in the sediments of the Anning River, with a total of 22 antibiotics detected. FQs were among the most abundant antibiotics, followed by TCs, MLs, APs, and SAs. The total concentrations of antibiotics in surface sediments varied from 0.05 to 53.35 ng/g, with an average of 8.09 ng/g. Among these groups, MLs, FQs, and TCs emerged as the predominant classes of antibiotics. The midstream sediments showed the highest residual levels of antibiotics, with lower levels observed in the downstream and upstream sediments. Anthropogenic activities, such as human clinical practices and animal breeding, might be sources of antibiotics released into the river. An ecological risk assessment revealed that trimethoprim from the SA group exhibited high risks, and MLs showed medium risks in the Anning River, whereas most antibiotics presented minimal to low risks. This study provides valuable information on antibiotic pollution in the upstream region of the Yangtze River, and future management measures are needed for the Anning River. [ABSTRACT FROM AUTHOR]

Cruciferae brassica oilseed rape is the third largest oilseed crop in the world and the first in China, as well as a fertilizer-dependent crop. With the increased application of organic fertilizers from livestock manure in agricultural production in recent years, the resulting antibiotic pollution and its ecological health effects have attracted widespread attention. In this study, typical tetracycline and sulfonamide antibiotics tetracycline (TC) and sulfamethoxazole (SMZ) were used to investigate the effects of antibiotics on rapeseed quality and oxidative stress at the level of secondary metabolism on the basis of examining the effects of the two drugs on the growth of soil-cultivated rapeseed seedlings. The results showed that both plant height and biomass of rapeseed seedlings were significantly suppressed and ROS were significantly induced in rapeseed by exposure to high concentrations (2.5 mg/kg) of TC and SMZ. Carotenoids, tocopherols, and SOD enzymes were involved in the oxidative stress response to scavenge free radicals in rapeseed, but phenolic acids and flavonoids contents were decreased, which reduced the quality of the seeds to some extent. [ABSTRACT FROM AUTHOR]

Antibiotic contamination has a significant negative impact on China, one of the largest producers and consumers of antibiotics worldwide. In this study, a three-dimensional flower-like structure of CoFe-LDHs was used to efficiently degrade tetracycline (TC) in a system triggered by peroxymonosulfate (PMS) and exposed to visible light. After exploring the effects of different metal ratios, catalyst dosage, initial TC concentrations, and pH, the optimal reaction conditions were determined. In comparison to pure CoFe-LDHs, the TC elimination rate was dramatically increased by the addition of the PMS. The strong environmental resistance, excellent stability and reusability, and universal flexibility were shown. The quenching experiments and electron spin resonance detection showed that the creation of reactive oxygen species was facilitated by the synergistic transmission of electrons between the active bimetallic components. Further, photogenerated holes was the dominant oxidizing species, which contributed more to the degradation of TC. The potential degradation pathways and intermediate toxicity of TC were suggested. This work offers a new method dominated by photogenerated holes for efficiently removing TC effluent. [ABSTRACT FROM AUTHOR]

Background The overuse of antibiotics in livestock is contributing to the burden of antimicrobial resistance in humans, representing a One Health challenge. Livestock-associated methicillin-resistant Staphylococcus aureus (LA-MRSA) has recently become a growing concern, and ST9 is the major LA-MRSA lineage in China and has emerged in clinical settings. Methods Antimicrobial susceptibility testing was used to evaluate the tetracycline resistance of ST9 MRSA collections, and gene cloning experiments were performed to explore the resistance mechanisms. Whole-genome sequencing and comparative genomics were used to analyse the genetic features of clinical ST9 isolates. A phylogenetic tree was constructed to investigate the relationship of human- and livestock-derived ST9 isolates. Results Clinical ST9 isolates were found to possess several types of resistance genes and resistance-related mutations and were multidrug-resistant. Notably, all clinical ST9 isolates were resistant to third-generation tetracyclines. Cloning experiments showed that both the acquisition of the tetracycline resistance gene tet (L)/ tet (63) and a mutation in the rpsJ gene contributed to third-generation tetracycline resistance. Phylogenetic analysis showed that the ST9 isolates collected in healthcare systems were probably transmitted from livestock. The ST9 lineage underwent multiple interspecies recombination events and gained many resistance elements. Furthermore, the resistance to third-generation tetracyclines may have evolved under tetracycline pressure in livestock. Conclusions The evolution of ST9 MRSA in livestock and transmission of this clone between humans and livestock highlight the importance of establishing control strategies with the One Health approach to reduce the burden of antibiotic resistance. [ABSTRACT FROM AUTHOR]

This paper summarizes the migration of tetracycline wastewater in the water environment and summarizes the technical difficulties of tetracycline wastewater treatment, elaborates on the common tetracycline wastewater treatment technologies in China: Biodegradation, physical adsorption, advanced oxidation, etc・, and the removal effect of each process type on tetracycline pollutants, summarize the new wastewater treatment technologies that can be applied to rural areas in the future, and look forward to the future development trend of tetracycline wastewater treatment to provide reference for future research on tetracycline wastewater treatment. [ABSTRACT FROM AUTHOR]

Adaptation to selective pressures is crucial for clinically important pathogens to establish epidemics, but the underlying evolutionary drivers remain poorly understood. The current epidemic of carbapenem-resistant Klebsiella pneumoniae (CRKP) poses a significant threat to public health. In this study we analyzed the genome sequences of 794 CRKP bloodstream isolates collected in 40 hospitals in China between 2014 and 2019. We uncovered a subclonal replacement in the predominant clone ST11, where the previously prevalent subclone OL101:KL47 was replaced by O2v1:KL64 over time in a stepwise manner. O2v1:KL64 carried a higher load of mobile genetic elements, and a point mutation exclusively detected in the recC of O2v1:KL64 significantly promotes recombination proficiency. The epidemic success of O2v1:KL64 was further associated with a hypervirulent sublineage with enhanced resistance to phagocytosis, sulfamethoxazole-trimethoprim, and tetracycline. The phenotypic alterations were linked to the overrepresentation of hypervirulence determinants and antibiotic genes conferred by the acquisition of an rmpA-positive pLVPK-like virulence plasmid and an IncFII-type multidrug-resistant plasmid, respectively. The dissemination of the sublineage was further promoted by more frequent inter-hospital transmission. The results collectively demonstrate that the expansion of O2v1:KL64 is correlated to a repertoire of genomic alterations convergent in a subpopulation with evolutionary advantages. Authors carry out a genomic analysis of carbapenem-resistant Klebsiella pneumoniae bloodstream isolates, noting subclonal expansion, associated with the emergence of a hypervirulent subpopulation. [ABSTRACT FROM AUTHOR]

Tetracycline (TC) can easily lead to persistent environmental toxicity via bio-enrichment effects, due to the inefficient bio-absorption, high solubility, and high bio-activity. Advanced oxidation processes based on sulfate radicals (SR-AOPs) can be expected to serve as an alternative means. Green low-cost biochar (BC) can be also used as an uneven catalyst. The persulfate (PS) was efficiently decomposed to generate the high-oxidation to restore power free radicals (OH, and SO4-·) during the degradation mineralization of organic matter. In addition, the annual waste bone production has reached 1348 tons in 2021 in China. Traditional treatments of waste bone can also be limited in the implementation conditions or cure such defects as bacterial reproduction. The waste bone can be prepared to catalyze the PS degradation TC. There are different properties of thermal temperature, crystallization, and surface shape made of BC, leading to the removal performance of pollutants. In this study, the different structures of pig bones coal with cooking pig bones were prepared as the raw materials at different temperatures of thermal resolution from 500 ℃ to 900 ℃. Energy spectroscopy was selected to analyze the effect of heat resolution on the pig bone's carbon shape, active phosphorus (hydroxyapatite, HAP) crystal structure, oxygenic acid, as well as the active functional units and cavity structure. Then, the material performance was compared to determine the optimal material pH, and PS parameters impact. The optimal system was achieved in the active oxygen sudden extinction to investigate the interaction between bone carbonization temperature and structure for the catalyst degradation performance. The results showed that there was a noticeable carbonization structure of the pig’s bone with the change in the carbonization temperature, indicating three distinct structures of layered cracks, needle-shaped clusters, and empty heart balls at three supply temperatures. Compared with 500 ℃ and 900 ℃, the crystalline structure formed at 700 ℃, and the fully volatile organic components presented the 700BPBC surface calcium phosphorus in the high-temperature formed crystal and the sp² structural carbon frame in the pig coal combined to form the needle-shaped fiber structure in the form of cluster. The more fine and shorter narrow conveyor was formed with a more microporous structure and better crystal comparison of phosphatic minerals. Energy and infrared spectrum analysis showed that the non-crystalline transformation was significantly influenced by the thermal resolution temperature, and then the content of C, O, Ca, and P, due to the full splitting of organic collagen and inorganic phosphorus and crystalline composition in HAp. As such, the 700BPBC was superior to the other two kinds of pig bone biochar with the rich -OH and active CHAp. The catalytic degradation experiment showed that the degrading capacity order from large to small is 700BPBC, 500BPBC, 900BPBC. Among them, the 700BPBC shared a stronger performance of catalytical degeneration for the TC, due to the small, narrow conveyor, rich active functional agglomeration spots, and better crystalline comparison. Furthermore, the ion form of quercetin was easier to capture than pig coal, when the solution environment was weakly acidic (pH value is 5). The best activity was achieved in the free radicals produced by sulfate (PS). The moderate overdose of sulphate (BC:PS = 1:6) produced the most effective free radical. The OH contributed the most under the 700BPBC/PS system. The free radical reaction was the dominant pathway to catalyze the degradation reaction. There were active CHAp and C=O-induced non-free radical reactions. [ABSTRACT FROM AUTHOR]

In recent years, antibiotics have been listed as a new class of environmental pollutants. Tetracycline antibiotics (TCs) used in human medical treatment, animal husbandry and agricultural production are the most widely used antibiotics. Due to their wide range of activities and low cost, their annual consumption is increasing. TCs cannot be completely metabolized by humans and animals. They can be abused or overused, causing the continuous accumulation of TCs in the ecological environment and potential negative effects on non-target organisms. These TCs may spread into the food chain and pose a serious threat to human health and the ecology. Based on the Chinese environment, the residues of TCs in feces, sewage, sludge, soil and water were comprehensively summarized, as well as the potential transmission capacity of air. This paper collected the concentrations of TCs in different media in the Chinese environment, contributing to the collection of a TC pollutant database in China, and facilitating the monitoring and treatment of pollutants in the future. [ABSTRACT FROM AUTHOR]

According to the findings of a sheep breeding farm in Shaanxi, China, 2.53% (15/594) of sheep exhibited respiratory (clinical) symptoms such as dyspnoea, nasal discharge, wet cough, fever, and progressive emaciation. Although multi-drug treatment strategies (including ampicillin, tylosin, florfenicol, and ceftiofur) have been attempted to improve clinical outcomes, they have only been met with limited success, with a mortality rate of 40%. Ultimately, Aeromonas veronii (A. veronii) was identified as the causative pathogen for respiratory disease. The rates of symptomatic and asymptomatic sheep positive to A. veronii were 64.28% (95% CI 52.25–76.31%) and 8.02% (95% CI 6.96–9.08%), respectively. Pathogenicity tests demonstrated that the A. veronii is pathogenic to sheep and mice. The results of the antibiotic susceptibility tests revealed that the strain was sensitive to cefotaxime, gentamicin, and enrofloxacin and resistant to ampicillin, ceftiofur, amoxicillin, kanamycin, neomycin, streptomycin, tetracycline, florfenicol, and tylosin. We suggest that the combination of cefotaxime and gentamicin is an effective treatment based on the results of an antimicrobial susceptibility test, which exhibited good therapeutic efficacy. To the best of our knowledge, this is the first report in which pathogenic A. veronii has been documented as the cause of death in sheep in China. We concluded that pathogenic A. veronii poses a potential risk to the industry of sheep husbandry. This study's findings can help guide prevention and treatment plans for A. veronii infection in sheep. [ABSTRACT FROM AUTHOR]

Turkey is the world's largest honey producer after China. Honey is one of Turkey's most important agricultural export products. Due to uncontrolled antibiotic sale and unconscious use, antibiotic residues in Turkish honey cause important problems in exports. The presence of antibiotic residues in honey can be harmful to human health. Antibiotic residue in honey is still a major problem worldwide. Antibiotic residues in honey were mostly caused by incorrect beekeeping practices, not from the environment. The aim of this study was to determine the neomycin and tetracycline residues in honey collected from the Erzurum province. For this purpose, 79 honey samples were analyzed by the enzyme-linked immunoassay method. Tetracycline residues were found to be between 2.1 and 47.08 ppb in 37 of 79 honey samples (46.8%) and had an average of 9.33 ppb, while 22 of the samples were below the minimum detection limit (<2 ppb). Neomycin residues could not be detected in 79 honey samples (minimum detection limit 15.63 ng/mL). There are no maximum residue limits established for antibiotics in honey according to the Turkish Food Codex regulations, which means honey should not contain antibiotics. As a result, it is believed that honey producers should be informed that it is not legal to use antibiotics in honey production. [ABSTRACT FROM AUTHOR]

Carbapenem-resistant Acinetobacter baumannii (CRAB) appeared more frequently in children and caused a great threat to global public health. It is urgent to investigate the carbapenem resistance and virulence of CRAB for clinicians to choose appropriate antibiotics. A retrospective study of 77 nonduplicated CRAB isolates was conducted. The carbapenem resistance and virulence genes were characterized by polymerase chain reaction (PCR) and gel electrophoresis. In the present study, A. baumannii mainly came from the intensive care unit and was mostly isolated from sputum samples. The carbapenem resistant rate of A. baumannii in 2018–2020 increased significantly compared with that in 2016–2017. All isolates had carbapenem resistant genes. They were highly resistant to a variety of antibiotics but were relatively sensitive to fluoroquinolones and tetracyclines. blaVIM and blaOXA-23 were detected in all isolates, whereas blaOXA-51, blaIMP and blaNDM were present in 98.70%, 67.53% and 31.17% of isolates, respectively. Notably, 1 isolate A. baumannii was identified as multidrug-resistant A. baumannii (MDR-AB), and 76 other extensively drug-resistance (XDR) isolates were also detected. Virulence genes were present in 100% of all isolates, including genes in the iron acquisition system (basJ), secretion systems (ompA, plcD), quorum sensing system (abaI) and biofilm formation (csuA). adeH, pgaA, and ptk were present in 98.70%, 98.70% and 94.80% of isolates, respectively. CRAB, which is prevalent in east China, carries a large number of drug resistance and virulence genes. Fluoroquinolones and tetracyclines may be effective antibiotics for the treatment of CRAB infection in children. An in-depth understanding of the resistance and virulence of CRAB is conducive to timely guiding empirical drug use and controlling infection. [ABSTRACT FROM AUTHOR]

Escherichia coli is considered an opportunistic pathogen and an indicator for antimicrobial resistance (AMR) monitoring. Despite many reports on its AMR monitoring, studies based on genome-based analysis of AMR genes are still insufficient. Here, 181 E. coli strains were isolated from anal swab samples collected from pigs and chickens of animal farms located in Eastern China and sequenced through the Illumina platform. The results showed that 87.85% (159/181) of the E. coli isolates were multidrug-resistant (MDR). Ampicillin (AMP)- spectinomycin (SPT)- tetracycline (TET)- florfenicol (FFC)- sulfisoxazole (SF)- trimethoprim/sulfamethoxazole (SXT) was the predominant AMR pattern. By whole-genome sequencing, we found that ST10 (10.49%, 19/181) and ST48 (7.18%, 13/181) were major sequence types. IncFIB and IncX1 were the most prevalent plasmid replicons. The AMR genes blaNDM-5 (1.10%, 2/181), mcr-1 (1.10%, 2/181), tet(X4) (1.10%, 2/181), and cfr (6.08%, 2/181) were also found in these isolates. In addition, among the 169 virulence genes detected, we identified astA (37.02%, 67/181), hlyA (1.66%, 3/181), hlyB (1.66%, 3/181) and hlyD (1.66%, 3/181), which were closely related to heat-stable enterotoxin 1 and α-hemolysin. In addition, there were 33 virulence genes associated with the iron uptake system, and 46 were adhesion-related genes. Our study highlighted the need for routine surveillance of AMR with advanced genomic approaches, providing up-to-date data on the prevalence of AMR for the development and execution of antimicrobial stewardship policy. [ABSTRACT FROM AUTHOR]

The increasing rates of antibiotic resistance in Helicobacter pylori (H. pylori) are a major concern of the decreasing eradication rate. Large-scale and long-period studies on antimicrobial susceptibility of H. pylori in children are limited. This study aimed to describe the temporal changes of antibiotic resistance among children in southeast China. Gastric biopsies obtained from children were cultured for H. pylori from 2015 to 2020. Susceptibility to clarithromycin (CLA), amoxicillin (AML), metronidazole (MTZ), furazolidone (FZD), tetracycline (TET) and levofloxacin (LEV) was tested. Data from 2012 to 2014 reported previously were obtained for comparing the change in temporal trends of antibiotic resistance. A total of 1638 (52.7%) H. pylori strains were isolated from 3111 children recruited. The resistance rates to CLA, MTZ and LEV were 32.8%, 81.7% and 22.8%, respectively. There were 52.9% strains resistant to single resistance, 28.7% to double resistance, and 9.0% to triple resistance. The total resistance rate and resistance rates to CLA, MTZ, LEV, CLA + LEV and CLA + MTZ + LEV increased annually in a linear manner. All resistant patterns except single resistance increased obviously from 2015 to 2017 and 2018 to 2020 compared to that from 2012 to 2014. Double resistance to CLA + MTZ increased significantly with age. The resistance rate to CLA and triple resistance to CLA, MTZ and LEV increased in children with prior H. pylori treatment than that from children without prior treatment. The antibiotic resistance rates of H. pylori were high in a large pediatric population in southeast China from 2015 to 2020. Individual treatment based on susceptibility test is imperative and optimal regimens should be chosen in H. pylori eradication therapy. [ABSTRACT FROM AUTHOR]

Photocatalysis, as a novel technique, has been widely used for antibiotic pollution remediation in wastewater. In the processes of degradation and removal of antibiotics, the impact of photocatalysts on microenvironment is very important but remains poorly understood. In the present study, the effect of typical photocatalyst g-C3N4 (Graphitic carbon nitride) on microbial community was investigated in two sediment types (riverbed sediment and pig-farm sediment) polluted by tetracycline (TC) in central southern China. The riverbed sediment and pig farm sediment samples were respectively exposed to g-C3N4 (25, 75, 125 mg.kg-1) and TC (60, 120, 180 mg.L-1) treatments alone or combination for 30 days, respectively. The bacterial community and antibiotic resistance genes (ARGs) of the treated sediments were analyzed by Illumina sequencing and metagenomic sequencing. Studies had shown that: TC, g-C3N4, and TC/g-C3N4 have significant effects on the changes of microbial communities and components in riverbed sediment, but they do not exist in pig farm sediment. The most alterations of microbial taxa were Acidobacteriota, Actinobacteriota, and Desulfobacterota in riverbed sediment, and Elusimicrobiota in the pig farm sediment under various treatments. Through network analysis, it was found that the distribution of microorganisms in the pig farm sediment is more complex and more stable. The addition of g-C3N4 reduced the absolute abundance of ARGs in the two examined sediments, but not significantly changed their relative abundance of ARGs. The g-C3N4 application was beneficial to the removal of TC residues and to the prevention of the generation and transmission of ARGs in sediments. Our results suggested that g-C3N4 was a suitable photocatalyst with excellent application prospect for the removal of TC residues and the control of ARGs in environment. [ABSTRACT FROM AUTHOR]

Yellow-feathered chickens have great nutritional value and are widely and traditionally used in China, on an industrial scale as broilers. The presence of intestinal microbes has been shown to correlate with poultry performance and serves as an essential reservoir of antibiotic resistance genes (ARGs). Antibiotic resistance is a major public health concern. Here, we investigated functional characteristics of the gut microbiome of indigenous Chinese yellow-feathered chickens (the Huiyang Bearded, Xinghua, Huaixiang, Zhongshan Shanlan, Qingyuan Partridge, and Yangshan chickens) through metagenomic sequencing and reconstructed 409 draft genomes, including 60 novel species and 6 novel genera. Furthermore, we assessed the functions of the intestinal microbial communities and examined the ARGs within them. The results showed that the microbial populations of yellow-feathered broilers were primarily dominated by Bacteroidetes and Firmicutes at the phylum level and Bacteroides at the genus level. Furthermore, the Qingyuan Partridge chicken showed a significantly higher abundance of Prevotella than the other five breeds of chicken. Principal coordinates analysis indicated significant differences in the structures of microbial communities and ARGs, based on the binary Jaccard distance, among the six chicken breeds. Moreover, 989 ARGs conferring tetracycline, multidrug, and aminoglycoside resistance were identified, which represented more than 80% of the faecal resistomes; the most abundant gene in the yellow-feathered chickens was tet(Q). In addition, we found the greatest abundance of resistance genes in Xinghua chickens, indicating that Xinghua chickens are highly resistant to antibiotics. Overall, our findings revealed differences in the gut microbial community structure of indigenous Chinese yellow-feathered broiler breeds and the composition and characteristics of ARGs and antibiotic resistance that enabled us to reconstruct the yellow-feathered chicken gut microbial community genomes. The current data significantly improves our knowledge of the gut microbiome and antibiotic resistance of popular broiler breeds in China. [ABSTRACT FROM AUTHOR]

Using electrospun chitosan/polyethylene oxide nanofibers mat (CS/PEO NFM) as carrier, Cu@CS/PEO NFM, a new tetracycline (TC) solid-state colorimetric sensor, were simply prepared by directly immobilizing Cu2+ on surface of CS/PEO NFM. After immersing in TC solutions, Cu@CS/PEO NFM can display visible color changes to the naked eye within 5.0 min, and the TC concentration-dependent color changes can also be quantitatively analyzed with a smartphone. Because Cu2+ can enhance the adsorption of CS/PEO NFM for TC, Cu@CS/PEO NFM possess a more sensitive response ability to TC, ensuring that the colorimetric sensing detection will not be interfered by other coexisting drugs. Due to the reversible combination of chitosan and Cu2+, the colorimetric sensing ability of Cu@CS/PEO NFM can be regenerated even after being reused at least 4 times. In addition, the naked eye detection limit of Cu@CS/PEO NFM-based colorimetric sensing is 65 μg kg−1, which does not exceed the maximum residue limit in milk samples set by China (100 μg kg−1). The obtained results fully indicated the practical application value of this method in preventing the hazard of TC residues. Graphical abstract [Display omitted] • Simple preparation process: directly immobilizing Cu2+ on surface of CS/PEO NFM • Ability to reuse: reused for 4 times without degeneration in sensing performance • Fast response speed: qualitative detection in just 5.0 min • Anti-interference ability: without interference by other coexisting drugs • Practical application value: as a new sensor for colorimetric detection of TC in milk [ABSTRACT FROM AUTHOR]

Aim: Understanding the prevalence of antibiotic resistance can provide reliable information for selecting treatment options. The goal of this meta-analysis was to observe the primary antibiotic resistance of Helicobacter pylori (H. pylori) in different regions and time periods of China. Method: We searched PubMed, EMBASE, Chinese Biomedical databases and the China National Knowledge Infrastructure from inception to 20 February 2022. Data on the prevalence of H. pylori primary resistance at various time points were included. A random-effect model was established to calculate the pooled antibiotic resistance. Results: In total, 2150 articles were searched, with 70 meeting the inclusion criteria. The resistance to clarithromycin, metronidazole, levofloxacin amoxicillin, tetracycline and furazolidone in 2016–2020 were 34% (95% CI: 30–39%), 78% (95% CI: 73–84%), 35% (95% CI: 30–40%), 3% (95% CI: 1–5%), 2% (95%CI: 1–4%) and 1% (95% CI: 0–4%), respectively. Clarithromycin showed regional difference, as the resistance was higher in northern (37%, 95% CI: 32–41%) and western China (35%, 95% CI: 17–54%) than that in southern (24%, 95% CI: 17–32%) and eastern China (24%, 95% CI: 20–28%). Conclusion: The resistance of H. pylori to clarithromycin and metronidazole was high and increased over time, whereas resistance to levofloxacin, amoxicillin, tetracycline and furazolidone remained stable. [ABSTRACT FROM AUTHOR]

Tetracyclines are widely used in Chinese apiculture. However, limited information is available on the presence of tetracycline residues in honey and the sources, degradation patterns, and associated health risks of these compounds. In this study, the presence of tetracyclines in honey samples across China was investigated over a four-year period. Additionally, the risks of dietary intake, as well as the sources and degradation patterns of tetracyclines in honey, were assessed. The three-dimensional spatial distributions (floral region, geographical region and entomological origin) of tetracyclines contamination varied significantly. Tetracycline residues in honey posed a moderate risk to children aged 3–10 years in Northwest China. Source analysis indicated that colony migration serves as the primary source of tetracyclines in honey. Based on the degradation patterns of tetracyclines in honey within colonies and during storage, oxytetracycline is more readily degraded than other tetracyclines. The main degradation products of tetracyclines are epimers and dehydration products, and the effects of these products on human health and the environment should be further evaluated in future studies. This comprehensive investigation provides valuable insights into the safe use and regulation of tetracyclines in Chinese apiculture. [Display omitted] • Tetracyclines profiles vary in honey samples from different sources. • OTC and TC exhibited the highest detection frequency and concentration. • Colony migration was the main source of tetracyclines in honey. • OTC was more readily degraded than other tetracyclines during production and storage. • Tetracyclines in honey posed moderate health risks to children aged 3-10 in NW China. [ABSTRACT FROM AUTHOR]

Emergence of bla NDM–1 and bla KPC–2 co-producing Klebsiella pneumoniae strains is currently attracting widespread attention, but little information is available about their tigecycline resistance, virulence, and prevalence in Southwest China. In July 2021, an extensively drug-resistant K. pneumoniae strain AHSWKP25 whose genome contained both bla NDM–1 and bla KPC–2 genes was isolated from the blood of a patient with the malignant hematological disease in Luzhou, China. We investigated the resistance profiles of AHSWKP25 using microbroth dilution, agar dilution, modified carbapenemase inactivation (mCIM), and EDTA-modified carbapenemase inactivation methods (eCIM). The virulence of AHSWKP25 was assessed through string tests, serum killing assays, and a Galleria mellonella larval infection model. Conjugation and plasmid stability experiments were conducted to determine the horizontal transfer capacity of plasmids. And efflux pump phenotype test and real-time quantitative reverse transcription-PCR (RT-PCR) were used to determine its efflux pump activity. Sequencing of AHSWKP25 determined that AHSWKP25 belonged to ST464, which is resistant to antibiotics such as carbapenems, tetracycline, fluoroquinolones, tigecycline, and fosfomycin. The efflux pump phenotype tests and RT-PCR results demonstrated that efflux pumps were overexpressed in the AHSWKP25, which promoted the tigecycline resistance of the bacteria. AHSWKP25 also showed hypervirulence and serum resistance in vitro model. AHSWKP25 carried several different plasmids that contained bla NDM–1, bla KPC–2, and mutated tet(A) genes. Sequence alignment revealed that the plasmids carrying bla NDM–1 and bla KPC–2 underwent recombination and insertion events, respectively. We demonstrated that an X3 plasmid carrying bla NDM–1 was transferred from pSW25NDM1 to E. coli J53. We also identified missense mutations in the ramR , rcsA , lon , and csrD genes of AHSWKP25. Our results highlighted the potential of bla NDM–1 and bla KPC–2 co-producing K. pneumoniae strains to further develop antimicrobial resistance and hypervirulent phenotypes, but measures should be taken to closely monitor and control the spread of superbugs with multidrug-resistant phenotypes and hypervirulence. [ABSTRACT FROM AUTHOR]

Photocatalysts have been widely prepared and used in wastewater treatment. Although the influence of photocatalyst application on survival and activity of organisms has been examined, its impact on composition and diversity of microbial community is not fully understood. In this study, the impact of photocatalyst g-C3N4 (Graphitic carbon nitride) on microbial communities in riverbed sediments polluted by antibiotic tetracycline (TC) was investigated. The sediment samples collected from the Xiangjiang River of China were exposed to different concentrations of TC, g-C3N4 and TC/g-C3N4 and the bacterial community were analyzed by Illumina sequencing. The results showed that the dominant bacterial phyla were Acidobacteriota, Proteobacteria, Actinobacteriota, and Chloroflexi in the study site. When compared to the control treatments, the application of TC, g-C3N4 and TC/g-C3N4 exhibited distinguishable effects on bacterial community structure in sediments. The presence of TC had greater influence on bacterial composition, while g-C3N4 and TC/g-C3N4 had less influence on bacteria. The diversity and richness of microorganisms in sediment increased under g-C3N4 application and reached the highest values when g-C3N4 was 75 mg/kg. The photocatalyst g-C3N4 restored bacterial community diversity affected by TC, reduced the TC residues in aquatic environment, and eliminated the side effects of TC application in sediments. Our study indicated that g-C3N4 was an environmentally friendly photocatalyst with lightly negative effects on microbial community in riverbed sediments, and could be used for effective remediation of TC-contaminated environments. [ABSTRACT FROM AUTHOR]

Purpose: The increasing drug resistance of Neisseria gonorrhoeae has become a serious public health concern. This study investigated N. gonorrhoeae isolates susceptibility to tetracycline antibiotics and the correlation between minimum inhibitory concentrations (MICs) of different antibiotics. The presence of resistance determinants in N. gonorrhoeae strains displaying different levels of tigecycline resistance was also compared. Methods: The minimum inhibitory concentrations (MICs) of tetracycline, minocycline, tigecycline, eravacycline, omadacycline on 412 N. gonorrhoeae isolates were measured by the agar dilution method. The MICs of ceftriaxone and azithromycin were also measured to determine the correlations between antibiotics by the value of the correlation coefficient R. The presence of resistance determinants was identified through polymerase chain reaction (PCR) and sequencing. Results: The MIC90 was 64mg/L for tetracycline, 64mg/L for minocycline, 0.5mg/L for tigecycline, 0.5mg/L for eravacycline, 4mg/L for omadacycline, 0.25 mg/L for ceftriaxone, and 1mg/L for azithromycin. The MIC90 and mode of tigecycline and eravacycline were much lower than those of tetracycline and minocycline. A poor correlation between omadacycline, eravacycline and tetracycline susceptibility was observed. Minocycline has a strong correlation with tetracycline. PorB1 typing, TetM-encoding plasmid, and mtrR promoter adenine deletion were significantly correlated with tigecycline MIC > 0.25mg/L. Conclusion: This study suggested that tigecycline and eravacycline had better in vitro activity and might be alternative antibiotics against resistant N. gonorrhoeae infections. Nevertheless, further in vitro experiments and clinical studies are needed for verification. [ABSTRACT FROM AUTHOR]

A field experiment was carried out in mudflats adjacent to the Yellow Sea, China, amended with sewage sludge and vermicompost by one-time input at different rates to reveal the fates of tetracycline resistance genes (TRGs) and their potential hosts in the soils. Quantitative PCR results showed that soils added with either sludge or vermicompost had more abundant TRGs compared with the non-fertilized soil. This situation was more obvious in sludge fertilized soils especially at high application rates. Vermicompost exhibited a promising outlook for improvement of the mudflats. The abundances of intI1 in the non-fertilized soils were significantly higher than those in fertilizers and fertilized soils. The potential hosts for intI1 were not shared with other TRGs-contained hosts, indicating that intI1 had little effects on the dissemination of TRGs in the mudflats. Moreover, the exclusive hosts for TRGs in fertilizers were not higher than those in the non-fertilized soils, illustrating little effects of fertilization on the introduction of exogenous TRGs into soil. The shared hosts between soil and fertilizers were highest among four possible sources, contributing vastly to the bloom of TRGs following fertilization. It was also shown that different organic fertilizers caused distinct categories of shared potential hosts for TRGs. RDA analysis further indicated that the abundances of the shared potential hosts were affected by soil nutrients. These results suggested that the development of TRGs in soil following fertilization depended on the shared potential hosts with similar ecological niches between soil and fertilizers. [ABSTRACT FROM AUTHOR]

A carbapenem-resistant Citrobacter sedlakii strain AA2CS carrying blaNDM-5 was detected in outdoor aerosols of a wastewater treatment plant (WWTP) in China and the whole genome was sequenced subsequently. AA2CS was captured in an aerobic tank with aerosol particles of sizes ranging from 4.7 to 7.0 μm. Besides blaNDM-5, AA2CS also harbored 21 other antibiotic resistance genes and displayed a high level of resistance to ampicillin, cefotaxime, ceftazidime, tetracycline, and meropenem. BlaNDM-5 was located on the IncX3 plasmid (pCSNDM-5) with an IS3000-IS5-blaNDM-5-bleMBL-trpF-dsbD-IS26 structure. pCSNDM-5 was highly homologous to other blaNDM-5-carrying IncX3 plasmids in China and can be transferred to the Escherichia coli recipient J53. To our knowledge, this is the first report of carbapenem-resistant Enterobacteriaceae in outdoor aerosols in WWTPs. [ABSTRACT FROM AUTHOR]

China is the world's largest livestock and poultry breeding country, but also the largest use of veterinary antibiotics. When a large amount of chicken manure is applied to the soil, it will cause the number of antibiotic residues and resistant bacteria to increase, which will bring about the pollution of antibiotic resistance genes (ARGs) in the soil, and then increase the risk of environmental pollution and human health. Field experiments were conducted to study the changes of soil tetracycline antibiotic residues, resistant bacteria and resistance genes treated with different types and dosage of chicken manure (no chicken manure, (CK), low fresh chicken manure treatment (300 kg·667 m−2), high fresh chicken manure treatment (600 kg·667 m−2), low decomposed chicken manure treatment (300 kg·667 m−2) and high decomposed chicken manure treatment (600 kg·667 m−2)). After one-year application of chicken manure, content of soil organic matter increased by 1.0%-3.2% compared with the control. The activity of soil catalase significantly increased by 84.3–91.5%, 81.9–102.9% in fresh and decomposed chicken manure treatments compared with the control, respectively. The amount of soil resistant bacteria under the same treatment was in the order of Anti-OTC > Anti-TC > Anti-CTC. After one-year application of chicken manure, the total tetracycline amount in the soil was increased by 168.5–217.9% compared with the control. The amount of antibiotic residue in soil treated with fresh chicken manure was 3.0–9.1% higher than that treated with decomposed chicken manure. The abundance of ARGs in the soil was in the order of that treated with high fresh chicken manure > low fresh chicken manure > high decomposed chicken manure > low decomposed chicken manure. The risk of tetracycline antibiotics to soil ecological environment may be greatly reduced after chicken manure decomposed. [ABSTRACT FROM AUTHOR]

As the most widely distributed scavenger birds on the Qinghai-Tibetan Plateau, Himalayan vultures ( Gyps himalayensis ) feed on the carcasses of various wild and domestic animals, facing the dual selection pressure of pathogens and antibiotics and are suitable biological sentinel species for monitoring antibiotic resistance genes (ARGs). This study used metagenomic sequencing to comparatively investigate the ARGs and mobile genetic elements (MGEs) of wild and captive Himalayan vultures. Overall, the resistome of Himalayan vultures contained 414 ARG subtypes resistant to 20 ARG types, with abundances ranging from 0.01 to 1,493.60 ppm. The most abundant resistance type was beta-lactam (175 subtypes), followed by multidrug resistance genes with 68 subtypes. Decreases in the abundance of macrolide-lincosamide-streptogramin (MLS) resistance genes were observed in the wild group compared with the zoo group. A total of 75 genera (five phyla) of bacteria were predicted to be the hosts of ARGs in Himalayan vultures, and the clinical (102 ARGs) and high-risk ARGs (35 Rank I and 56 Rank II ARGs) were also analyzed. Among these ARGs, twenty-two clinical ARGs, nine Rank I ARG subtypes, sixteen Rank II ARG subtypes were found to differ significantly between the two groups. Five types of MGEs (128 subtypes) were found in Himalayan vultures. Plasmids (62 subtypes) and transposases (44 subtypes) were found to be the main MGE types. Efflux pump and antibiotic deactivation were the main resistance mechanisms of ARGs in Himalayan vultures. Decreases in the abundance of cellular protection were identified in wild Himalayan vultures compared with the captive Himalayan vultures. Procrustes analysis and the co-occurrence networks analysis revealed different patterns of correlations among gut microbes, ARGs, and MGEs in wild and captive Himalayan vultures. This study is the first step in describing the characterization of the ARGs in the gut of Himalayan vultures and highlights the need to pay more attention to scavenging birds., Competing Interests: The authors declare there are no competing interests., (©2024 Zhai et al.)

Background: Current guidelines recommend bismuth-containing quadruple therapy for patients newly diagnosed with Helicobacter pylori (H. pylori) infection. We aimed to compare the efficacy and safety of tetracycline administered three times daily versus four times daily in bismuth-containing quadruple therapy for first-line treatment of H. pylori infection., Methods: This multicenter, noninferiority, randomized controlled study, conducted in China, recruited treatment-naïve adults with H. pylori infection, randomized 1:1 into two treatment groups to receive either of the following bismuth-containing quadruple therapies: esomeprazole 20 mg twice-daily; bismuth 220 mg twice-daily; amoxicillin 1000 mg twice-daily; and tetracycline 500 mg three times daily (TET-T) versus 500 mg four times daily (TET-F). At least 6 weeks post-treatment, a 13 C-urea breath test was performed to evaluate H. pylori eradication., Results: In total, 406 patients were randomly assigned to the two treatment groups. Intention-to-treat eradication rates were 91.63% (186/203; 95% confidence interval [CI] 87.82%-95.44%) versus 90.15% (183/203; 95% CI 86.05%-94.25%) (p = 0.0005) and per-protocol eradication rates were 95.34% (184/193; 95% CI 92.36%-98.31%) versus 95.72% (179/187; 95% CI 92.82%-98.62%) (p = 0.0002) for the TET-T and TET-F group, respectively. TET-T-treated patients had a lower incidence of adverse effects than TET-F-treated patients (21.61% vs. 31.63%, p = 0.024), with no significant differences in compliance to treatment between the groups., Conclusion: As a first-line therapy for H. pylori infection, the eradication rate of the TET-T therapy was noninferior to that of the TET-F therapy while significantly reducing the incidence of adverse reactions., Trial Registration: ClinicalTrials.gov identifier: NCT05431075., (© 2024 John Wiley & Sons Ltd.)

The antibiotic distributions, partitioning, and migration pathways in river basins have withdrawn great attention in the past decades. This study investigates 26 antibiotics of five classifications in surface water and sediment samples at 23 sites in Fenhe River, a typical tributary of Yellow River. There are 21 antibiotics found in the water samples at the concentration from 113.8 to 1106.0 ng/L, in the decreasing order of SAs > QNs > MLs > TCs > CAs. Fifteen antibiotics were detected in the sediment at the concentrations from 25.11 to 73.22 μg/kg following the decreasing order of SAs > MLs > TCs > QNs > CAs. The antibiotic concentrations vary greatly in surface water, generally lower in upstream and in reservoirs, and reaching highest in the midstream of the Fenhe River after passing Taiyuan and Jinzhong, and then lower again in the downstream. The antibiotic concentrations in sediment have a less variation in the entire river basin, but become high in the downstream. The results show the water-sediment partitioning coefficients of antibiotics generally were lower than those in other areas, having a migration path from the water to suspended solids, and then accumulated in sediment. The water-sediment partitioning coefficients also vary across the basin. The water-sediment partitioning coefficients of sulfacetamide and tetracycline are higher than the water-sediment partitioning coefficients of other antibiotics, with less variation across the basin, the water-sediment partitioning coefficients of azithromycin, enrofloxacin, and roxithromycin are low in the midstream of the river, and high at the river source and downstream. The water-sediment partitioning coefficients are significantly affected by the pH of sediment and the particle size of sediment. The prediction models of water-sediment partitioning coefficients for antibiotics are constructed with the selected effecting factors. The simulation values of antibiotics except chlortetracycline and erythromycin are highly consistent with the observed values, indicating that the prediction model is reliable. [ABSTRACT FROM AUTHOR]

Tetracycline, an animal antibiotic, may remain in milk to cause harm to human health. For economic reasons, the abuse of antibiotics is becoming more and more common. Therefore, the abuse of tetracycline has alarmed the dairy industry and many countries such as New Zealand, China, and the USA have proposed strict standards. Surface-enhanced Raman scattering (SERS) is an emerging detection method which has been applied in food detection with the advantages of no complex pretreatment, fast detection, and weak water environment interference. Considering the abuse of antibiotics in dairy industry, we used polydimethylsiloxane (PDMS) plasma cavity as SERS substrate to detect tetracycline in milk. We found that the enhancement ability of PDMS substrate is affected by addition of 4-amino-1-butanol and complex interplay in the milk--tetracycline system. The modified PDMS plasma cavity has high SERS sensitivity that allows us to achieve low detection limit of 0.28 μ g/L. The correlation coefficient was 0.987. The detection of tetracycline in milk using PDMS substrate is quick (within 10 min) and it provides a possible method for in-site detection of tetracycline. [ABSTRACT FROM AUTHOR]

This study aimed to characterize 16S rRNA methylase genes among Salmonella and to elucidate the structure and evolution of rmtB -carrying plasmids. One hundred fifty-eight Salmonella isolates from one pig slaughterhouse were detected as containing 16S rRNA methylase genes; two (1.27%) Salmonella London isolates from slaughtered pigs were identified to carry rmtB. They were resistant to gentamicin, amikacin, streptomycin, ampicillin, tetracycline, florfenicol, ciprofloxacin, and sulfamethoxazole/trimethoprim. The complete sequences of RmtB-producing isolates were obtained by PacBio single-molecule real-time sequencing. The isolate HA1-SP5 harbored plasmids pYUHAP5-1 and pYUHAP5-2. pYUHAP5-1 belonged to the IncFIBK plasmid and showed high similarity to multiple IncFIBK plasmids from Salmonella London in China. The rmtB -carrying plasmid pYUHAP5-2 contained a typical IncN-type backbone; the variable region comprising several resistance genes and an IncX1 plasmid segment was inserted in the resolvase gene resP and bounded by IS 26. The sole plasmid in HA3-IN1 designated as pYUHAP1 was a cointegrate of plasmids from pYUHAP5-1-like and pYUHAP5-2-like, possibly mediated by IS 26 via homologous recombination or conservative transposition. The structure differences between pYUHAP1 and its corresponding part of pYUHAP5-1 and pYUHAP5-2 may result from insertion, deletion, or recombination events mediated by mobile elements (IS 26 , IS CR1 , and IS Kpn43). This is the first report of rmtB in Salmonella London. IncN plasmids are efficient vectors for rmtB distribution and are capable of evolving by reorganization and cointegration. Our results further highlight the important role of mobile elements, particularly IS 26 , in the dissemination of resistance genes and plasmid evolution. [ABSTRACT FROM AUTHOR]

Background: The aim was to determine the potential association of the gut microbiota composition, especially the abundance of Actinobacteria, as well as the differentiation of functional and resistance genes with age (young adults vs elderly subjects) in China. Results: The patterns of relative abundance of all bacteria isolated from fecal samples differed between young adults and elderly subjects, but the alpha diversity (Chao1 P = 0.370, Shannon P = 0.560 and Simpson P = 0.270) and beta diversity (ANOSIM R = 0.031, P = 0.226) were not significantly different. There were 3 Kyoto Encyclopedia of Genes and Genomes (KEGG) metabolic pathways (carbon metabolism, inositol phosphate metabolism, and sesquiterpenoid and triterpenoid biosynthesis) and 7 antibiotic resistant genes (ARGs) (macrolide lincosamide-streptogramin B (MLSB), tetracycline, aminoglycoside, sulfonamide, fosmidomycin, lincomycin, and vancomycin) that showed significant differences between the 2 groups (all P < 0.05). The abundance of Actinomycetes was enriched (about 2.4-fold) in young adults. Bifidobacteria dominated in both young adults and elderly subjects, with overall higher abundances in young adults (P > 0.05). Only the Bifidobacterium_dentium species showed significant differences between the 2 groups (P = 0.013), with a higher abundance in elderly subjects but absent in young adults. Conclusions: The present study revealed that there were 3 KEGG metabolic pathways and 7 ARGs as well as enhanced Bifidobacterium_dentium species abundance in elderly compared to young subjects. [ABSTRACT FROM AUTHOR]

To investigate the distribution, contamination status, and antibiotic resistance of Listeria monocytogenes in four types of retail poultry meat, including chicken, duck, goose, and pigeon, sold in Jiading District, Shanghai, a total of 236 retail poultry meat samples were collected, and L. monocytogenes isolates were obtained for identification and antibiotic susceptibility testing against 14 common antibiotics. Forty-one L. monocytogenes isolates were detected from the 236 retail poultry meat samples, with detection rates of 24.47%, 19.44%, 14.75%, and 4.44% in chicken, goose, duck, and pigeon meat, respectively. Among refrigerated, frozen, and room temperature samples, refrigerated poultry had the highest detection rate at 25.40%, while frozen poultry had the lowest at 13.33%. The detection rate of L. monocytogenes in chicken meat differed significantly between the storage temperatures, while no significant differences were found for other poultry types. No significant differences in detection rates were observed between different retail locations or packaging methods. Isolates exhibited complete resistance to cefoxitin (FOX) and increasing resistance over time to tetracycline (TET) and clindamycin (CLI), while low levels of resistance were found for penicillin (PEN), oxacillin (OXA), and erythromycin (ERY). Resistance to ERY and TET suggests the potential for multidrug resistance. Significant differences in antibiotic resistance profiles were observed among L. monocytogenes from the various poultry types. In summary, contamination status and antibiotic resistance profiles differed among retail chicken, duck, goose, and pigeon meat sold and the resistance rate of strains continues to increase in Jiading District, Shanghai. Targeted control measures should be implemented to reduce the emergence of resistant strains, as retail conditions had minimal impact on L. monocytogenes prevalence in poultry meat., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

The purpose of this research was to characterize the antibiotic resistance profiles of Campylobacter spp. derived from chicken and pig feces collected from farms in Jiangsu Province, China, and to analyze the relevant resistance mechanisms among antimicrobial-resistant Campylobacter spp. isolates. Antibiotic susceptibility to nine antibiotic agents was tested with the microdilution method in 93 Campylobacter spp. (45 C. jejuni and 25 C. coli from chickens; 23 C. coli from pigs). High rates of resistance were observed to nalidixic acid (79.6%), erythromycin (75.3%), tetracycline (68.8%), azithromycin (66.7%), ciprofloxacin (64.5%), and gentamicin (35.5%), with a lower resistance rate to florfenicol (8.6%). The prevalence of the tested antibiotic resistance in C. coli was higher than in C. jejuni from chickens. The rate of antimicrobial resistance to ciprofloxacin in C. coli isolates from chickens was 100.0%, and the C. coli isolates from pigs were all resistant to erythromycin (100%). Most of C. jejuni (64.4%) and C. coli (64.5%) isolates displayed multi-drug resistance. All the Campylobacter spp. isolates resistant to fluoroquinolones had the C257T mutation in the gyr A gene. All 64 tetracycline-resistant Campylobacter spp. isolates were positive for the tet O gene. The tet A gene was also amplified in 6.5% of Campylobacter spp. isolates, whereas tet B was not detected among the isolates. The A2075G point mutation in the 23S rRNA gene occurred in 86.1% (62/72) of the macrolides-resistant Campylobacter spp. isolates, and the erm B gene was identified in 49 Campylobacter spp. isolates (30 C. jejuni and 19 C. coli). Amino acid insertions or mutations in the L4 and L22 ribosomal proteins were not linked to macrolide resistance. These results highlight the high prevalence of resistance to multiple antibiotics, particular macrolides, among Campylobacter spp. from chickens and pigs in Jiangsu Province, China, which is probably attributable to the overuse of antimicrobials in chicken and pig production. These findings recommend the more cautious use of critical antimicrobial agents in swine and poultry production. Stringent and continuous surveillance is required to reduce the drug-resistant campylobacteriosis in food animals and humans. [ABSTRACT FROM AUTHOR]

Objectives: To report a novel tigecycline resistance gene, tet(X6), and its variants in four bacterial species isolated from chickens and pigs in China.Methods: WGS was conducted to identify the suspected resistance genes in the tigecycline-resistant Myroides phaeus 18QD1AZ29W. Functional cloning, homology modelling and molecular docking were performed to compare the function with other Tet(X) variants. Retrospective screening for tet(X6) was conducted for 80 isolates in our WGS data collection, and all genomic environments of tet(X6)-positive isolates were analysed.Results: The tigecycline-resistant M. phaeus 18QD1AZ29W isolated from a pig farm in Shandong in 2018 was positive for tet(X2) and a novel tet(X) gene, designated tet(X6). Tet(X6) could increase the MICs of all tested tetracyclines/glycylcyclines for Escherichia coli only 2- to 4-fold, which was possibly due to a lower tetracycline binding capacity of Tet(X6) compared with that of other Tet(X) variants. Retrospective screening showed that seven other isolates (7/80, 8.8%), comprising four Proteus spp. and three Acinetobacter spp. from chickens and pigs in Shandong and Guangdong, were positive for three different variants of tet(X6). The analysis of the genomic environment revealed that two tet(X6)-positive isolates from M. phaeus and Proteus cibarius, respectively, contained ISCR2, which may play a role in tet(X6) transmission.Conclusions: This study identified a novel type of tigecycline resistance gene, tet(X6), in Myroides, Acinetobacter and Proteus from chickens and swine. Tet(X6) conferred lower tetracycline/glycylcycline MICs than other Tet(X) variants, and ISCR2 may play a role in the transmission of tet(X6). [ABSTRACT FROM AUTHOR]

Objectives: The continuous emergence of ceftriaxone-resistant Neisseria gonorrhoeae strains threatens the effectiveness of current treatment regimens for gonorrhoea. The objective of the present study was to characterize three ceftriaxone-resistant N. gonorrhoeae strains with a novel mosaic penA allele isolated in China.Methods: Three ceftriaxone-resistant Neisseria gonorrhoeae strains (GC150, GC161 and GC208) isolated in 2017 were characterized by N. gonorrhoeae multiantigen sequence typing (NG-MAST), MLST and N. gonorrhoeae sequence typing for antimicrobial resistance (NG-STAR). Recombination analyses were performed using the SimPlot software.Results: Three strains had the same antibiotic resistance profiles, with resistance to ceftriaxone (MIC 0.5 mg/L), ciprofloxacin (MIC 8.0 mg/L), penicillin (MIC 2.0 mg/L) and tetracycline (MIC 2.0-8.0 mg/L). STs were assigned as MLST7360, NG-MAST14292 and NG-STAR1611/NG-STAR1612. The penA gene of these three strains differed from previous ceftriaxone-resistant gonococcal strains and harboured a novel mosaic allele (penA-121.001). Like N. gonorrhoeae FC428, a widely disseminated ceftriaxone-resistant strain that was initially described in Japan in 2015, all strains also possessed substitutions A311V and T483S in PBP2, which are associated with resistance to ceftriaxone. Potential recombination events were detected in penA between N. gonorrhoeae strain FC428 and commensal Neisseria species. Our results provide further evidence that the commensal Neisseria species (Neisseria cinerea and Neisseria perflava) can serve as a reservoir of ceftriaxone resistance-mediating penA sequences in clinical gonococcal strains.Conclusions: The emergence of such strains may be the result of the interspecies recombination of penA genes between N. gonorrhoeae strain FC428 and commensal Neisseria species. [ABSTRACT FROM AUTHOR]

Background: To investigate the antibiotic resistance of Helicobacter pylori (H. pylori) strains to clarithromycin, metronidazole, amoxicillin, levofloxacin, furazolidone, and tetracycline in Chinese children., Materials and Methods: This multicenter, retrospective study was conducted from January 2016 through May 2023. Gastric mucosa biopsies were obtained from pediatric participants who underwent upper gastrointestinal endoscopy at 96 hospitals in northern, southwestern, and southeastern China. The susceptibility of H. pylori to six commonly used antibiotics was determined by agar dilution method., Results: Among the 3074 H. pylori isolates, 36.7% were resistant to clarithromycin, 77.3% to metronidazole, 16.6% to levofloxacin, and 0.3% to amoxicillin. No strains were detected to be resistant to furazolidone or tetracycline. During the 8-year study period, resistance to clarithromycin and metronidazole showed a significant upward trend, while the resistance pattern of the other antibiotics demonstrated a slight but nonsignificant fluctuation. Significant regional differences were found in the distribution of clarithromycin resistance among the northern (66.0%), southwestern (48.2%), and southeastern (34.6%) regions. The metronidazole resistance rate was significantly lower in the southeastern coastal region (76.3%) than in the other two regions (88.2% in the north and 87.7% in the southwest). Multi-drug resistance for two or more antibiotics was detected in 36.3% of the H. pylori strains, and the predominant multi-resistance pattern was the dual resistance to clarithromycin and metronidazole., Conclusions: The prevalence of H. pylori resistance to clarithromycin and metronidazole is rather high in Chinese children and has been increasing over time. A relatively high resistance rate to levofloxacin was also noticed in children, while almost all strains were susceptible to amoxicillin, furazolidone, and tetracycline. It will be of great clinical significance to continuously monitor the antibiotic-resistance patterns of H. pylori in the pediatric population., (© 2023 John Wiley & Sons Ltd.)

Given the ubiquitous detection of antibiotics and antibiotic resistance genes (ARGs) in waterbodies worldwide and increasing public attention to water resource safety, this study investigated the presence of antibiotics and ARGs in the water sources of the Wuhan stretch of the Yangtze River (YR) as well as potential ecological risks. In this study, 15 antibiotics and 10 ARGs in a source of drinking water were analyzed using solid-phase extraction-ultra performance liquid chromatography-mass spectrometry technology (SPE-UPLC-MS/MS) and real-time fluorescence quantitative polymerase chain reaction (qPCR). Fourteen antibiotics were detected in the samples from 18 water sources, with the highest concentration detected for tetracycline, reaching up to 1708.33 ng/L. The detection rates of norfloxacin, enrofloxacin, ofloxacin, tetracycline, and roxithromycin were 100%. The concentrations of antibiotics were highest in She Shui, followed by the Wuhan stretch of the lower reaches of the YR, whereas the lowest concentrations were found in the Wuhan stretch of the upper reaches of the YR which were approximately equal to those in the Han River (HR). Ofloxacin and roxithromycin presented a substantial threat to aquatic organisms with high sensitivity at the majority of the sampling sites. The overall abundance of ARGs was notably greater in the lower reaches of the YR compared with the upper reaches and the HR. The highest absolute abundance was observed for sulfa ARGs. Integron intl1 strongly correlated with sul1, sul2, ermB, and qnrS, and antibiotics, strongly correlated with multiple ARGs, suggesting that antibiotics and ARGs are present in water sources in Wuhan and may present a plausible hazard to both human and ecological well-being. Hence, regulating the spread and dissemination of antibiotics and ARGs in the environment is imperative. The findings of this research offer significant insights into the stewardship and safeguarding of aquatic reserves in the Wuhan stretch of the YR., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

To investigate the environmental pollution status of antibiotics in China on a national scale, a large number of the latest pollution data of antibiotics in water, sediment, and soil were collected, and ecological risks of antibiotics were evaluated using the risk quotients (RQs). The results showed that water, sediments, and soils in different parts of China were contaminated with antibiotics to varying degrees; antibiotics pollution of water bodies was relatively severe in the south of China but moderate in the west. The ecological risk assessment revealed that erythromycin, roxithromycin, tetracycline, colistin, sulfamethoxazole, and norfloxacin were high-risk pollutants in water, accounting for 20.9% of the total antibiotics, and were mainly distributed in Shandong, Hubei, Zhejiang, Sichuan, Guangdong, Hainan, Jiangsu, and Jiangxi provinces. Furthermore, norfloxacin was identified as the primary high-risk pollutant in river sediments, such as those of the Yellow River, Haihe River, Liaohe River, and Pearl River, accounting for 11.11% of all antibiotics. In contrast, tetracycline, tylosin, colistin, and norfloxacin were the main high-risk pollutants in aquaculture sediments, accounting for 72.5% of the total. In soil, tetracycline and colistin contents comprised a high ratio of the total amount (up to 28.6%); these were mainly distributed in Liaoning, Sichuan, Tianjin, and Shandong provinces. Relevant authorities should focus on the above-mentioned high-risk regions. This study provides sufficient scientific basis and data support for preventing and controlling antibiotic pollution in China.

Objective: To understand the antimicrobial resistance and genome characteristics of Campylobacter isolates recovered from retailed poultry meat samples in 20 provinces in China in 2020. Methods: In 2020, 265 Campylobacter strains including 244 Campylobacter jejuni and 21 Campylobacter coli collected from retailed poultry meat samples in China were tested for antimicrobial resistance to 9 antimicrobial compounds by using the agar dilution method. Forty-two selected isolates were sent for whole genome sequencing and 38 high-quality genomes were analyzed for their antimicrobial resistance genes, virulence genes, sequence types and genetic diversity. Results: The resistance rates of Campylobacter isolates from poultry meats to tetracycline, nalidixic acid and ciprofloxacin were the highest (84%-100%), with 53.2% of the isolates showing multidrug resistance in this study. The resistance rates of C. coli to erythromycin, azithromycin, telithromycin, gentamicin and clindamycin were significantly higher than those of C. jejuni ( P <0.05). The resistance genes conferring resistance to β-lactams (100%, 38/38), quinolones (94.7%, 36/38), tetracycline (81.6%, 31/38) and aminoglycosides (50%, 19/38) were the most frequently detected among 38 Campylobacter genomes. C. jejuni carried more virulence genes than C. coli . In total, 19 and 17 sequence types (ST) were obtained from 20 sequenced C. jejuni and 18 C. coli isolates, respectively, including 5 novel STs. The isolates showed a high genetic diversity based on their sequence types. Conclusion: The phenomenon of antimicrobial resistance in Campylobacter from poultry meat sources in China is relatively serious, and resistance and virulence genes are widely distributed in Campylobacter . There is genetic diversity in Campylobacter.

Exposure to tetracycline in soil causes microbial mutations. Soil microbial fuel cells (MFCs) can promote the degradation efficiency of contaminants while generating bioelectricity under anaerobic conditions. MFC performance varies amongst different types of soils due to distinctive soil properties. This study assesses the performance of soil MFCs filled with four typical Chinese soils and explores key factors regulating bioelectricity generation and tetracycline degradation. Except for the MFCs filled with black soil, tetracycline degradation rates improved in soil MFCs, particularly in those filled with Chao soil, which enhanced the degradation rate by 39% relative to the corresponding control. Additionally, soil MFCs filled with Chao soil exhibited the highest charge output of 1347 ± 357C, which was 100–499% higher than that of MFCs with other soils. According to redundancy analysis, soil particle size, pH, conductivity and dissolved organic carbon content showed positive association with tetracycline degradation and charge output, while the adsorption of tetracycline had a negative association with degradation rate. Thus, the adsorption of tetracycline restricted its removal efficiency in soil MFCs, and high soil conductivity and large particle size promoted electron transfer, enhancing biocurrent intensity, which increased tetracycline degradation efficiency. Unlabelled Image • Polluted Chao soil is suitable for bioelectrochemical remediation. • Soil pH and DOC play an important role in the efficiency of a soil MFC. • Higher EC and larger particle size favour the electron transfer circulation. • Tetracycline degradation in soil MFCs is controlled by ad/desorption. • Tetracycline adsorption is reduced by the directional migration of cations in MFCs. [ABSTRACT FROM AUTHOR]

In this study, the prevalence, phenotypes, and clonal relationships of Escherichia coli (E. coli) strains isolated from minks were investigated. In July 2017, a total of 62 fresh faecal swab samples were randomly collected from one large-scale mink farm in Zhucheng, Shandong Province, China. In all the samples, 50 E. coli strains were isolated and then assigned to serotyping, antimicrobial susceptibility test, detection of antimicrobial resistance genes and the Class 1 integrons, and multilocus sequence typing (MLST). Four pathogenic serotypes were identified among all the isolates, while the most common serotype was enterohemorrhagic E. coli O104:H4 (6.0 %). Antimicrobial sensitivity testing revealed that most isolates were susceptible to cefoxitin (96.0 %) and amikacin (82.0 %), while most isolates were resistant to ampicillin (92.0 %) and tetracycline (90.0 %). An analysis of the nucleotide sequences revealed that 7 isolates (14.0%) carried 4 types of Class 1 integron cassette, including dfrA27+aadA2+qnrA (57.1%), dfrA17+aadA5 (14.3%), dfrA12+aadA2 (14.3%), and dfrA1+aadA1 (14.3%). PCR screening showed that 14 antibiotic resistance genes were presented in 50 isolates, while the most prevalent resistance gene was qnrS, which was detected in 60.0 % of isolates, followed by sul2 (40.0%) and oqxA (38.0%). MLST analysis showed that 32 sequence types (STs) were identified, while ST46 was the predominant genotype among all isolates. Clonal complex 3 (CC3) was dominant. Compared with 340 human E. coli STs reported in China, the ST10 clonal complex, known as the largest human clonal complex, was also found in the 50 mink E. coli isolates. Meanwhile, mink-derived strain ST206 formed a new clonal complex, CC206, which was different from human ST strains. Our results showed that farmed minks could be reservoirs of antimicrobial-resistant E. coli with Class 1 integron cassettes and resistance genes, which were likely to pose a threat to public health. Therefore, continuous inspections and monitoring of E. coli in minks are essential for detecting and controlling emerging E. coli with different serovars as well as antibiotic resistance. [ABSTRACT FROM AUTHOR]

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Tet(M)-type proteins confer resistance to tetracycline and related antibiotics by interacting with the ribosome. Genes encoding Tet(M) have been found in a range of bacteria, including Escherichia coli. In the current study, conjugation experiments were performed between seven different tetracycline-resistant, azide-susceptible E. coli strains isolated from ducks and tetracycline-sensitive, azide-resistant E.coli J53. Transconjugants were obtained from two of the strains at a frequency of 1.2 × 10−8. PCR, southern blotting and sequencing demonstrated that tet (M) in the transconjugants was located on a ~50 kb IncHI2-type plasmid and was part of a composite transposon, designated Tn6539. This transposon is flanked by two IS26 elements in opposite orientation and contains the Tn3Δ tnpA +Δ orf13 - lp - tet (M)+gamma delta+ tnpX +Δ tnpR sequences. The Δ orf13 - lp - tet (M) sequence was a highly conserved genetic fragment in E. coli harboring tet (M) and mainly located in the composite transposons flanked by IS6-family elements. In summary, Tn6539 is a new composite transposon capable of horizontal transfer of tet (M) among E. coli isolates. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the antimicrobial resistance and virulence genes of Enterococcus faecalis isolated from subclinical bovine mastitis cases in China. Enterococcus faecalis isolates were identified by 16S rRNA amplification and sequencing. Antimicrobial susceptibility was determined by the disc diffusion method. Antimicrobial resistance and virulence genes were tested by PCR. Overall, E. faecalis was recovered from 81 of 1,787 (4.5%) mastitic milk samples. The isolates showed high resistance against tetracycline (87.7%) and erythromycin (79.0%). The most prevalent resistance genes found in the E. faecalis were tetK (96.3%), tetL (79.0%), and tetM (87.7%) for tetracycline and ermC (97.5%) for erythromycin. Moreover, gelE (70.4%), esp (85.2%), efaA (91.4%) were the most common virulence genes. This is the first report to characterize E. faecalis recovered from subclinical bovine mastitis cases in China. [ABSTRACT FROM AUTHOR]

Accounting for more than half of the total primary microplastic (MP) emissions, and one-sixth of the total marine MP pollution in China in 2015, tire wear particles (TWP) are inevitable to age and interact with co-existing species, thus pose a potential risk to the surroundings. The impacts of simulated ultraviolet radiation weathering and liquid-phase potassium persulfate oxidation of TWP on the surface physicochemical properties were comparatively explored. The characterization results demonstrated that the content of carbon black, particle size and specific surface area of the aged TWP all decreased, while the changes of the hydrophobicity and polarity were inconsistent. The interfacial interactions with tetracycline (TC) in aqueous were investigated, the well fitted pseudo-second-order kinetics, Dual-mode Langmuir and Scatchard isotherm models indicated the attachment of TC dominated by surface adsorption at lower concentration, and there's a positive synergistic effect among the main sorption domains. Moreover, the results of the influences of co-existing salts and natural organic matter revealed that the potential risks of TWP elevated by the adjacent media in natural compartment. This work provides new insights into the way that TWP interact with contaminants in the real environment. [Display omitted] • The content of carbon black and particle size of TWP decreased with aging. • A positive synergistic effect of different sorption domains of TWP was observed. • The surface adsorption was dominant at lower TC concentrations. • Polarity and hydrophobic interactions were the main driving forces. • Environmental factors enhanced the capture capability of TWP. [ABSTRACT FROM AUTHOR]

Background: Clostridioides difficile is a bacterium that causes antibiotic-associated infectious diarrhea and pseudomembranous enterocolitis. The impact of C. difficile infection (CDI) in China has gained significant attention in recent years. However, little epidemiological data are available from Chongqing, a city located in Southwest China. This study aimed to investigate the epidemiological pattern of CDI and explore the drug resistance of C. difficile isolates in Chongqing., Methods: A case-control study was conducted to investigate the clinical infection characteristics and susceptibility factors of C. difficile. The features of the C. difficile isolates were evaluated by testing for toxin genes and using multi-locus sequence typing (MLST). The susceptibility of strains to nine antibiotics was determined using agar dilution technique., Results: Out of 2084 diarrhea patients, 90 were tested positive for the isolation of toxigenic C. difficile strains, resulting in a CDI prevalence rate of 4.32%. Tetracycline, cephalosporins, hepatobiliary disease, and gastrointestinal disorders were identified as independent risk factors for CDI incidence. The 90 strains were classified into 21 sequence types (ST), with ST3 being the most frequent (n = 25, 27.78%), followed by ST2 (n = 10, 11.11%) and ST37 (n = 9, 10%). Three different toxin types were identified: 69 (76.67%) were A + B + CDT - , 12 (13.33%) were A - B + CDT - , and 9 (10%) were A + B + CDT + . Although substantial resistance to erythromycin (73.33%), moxifloxacin (62.22%), and clindamycin (82.22%), none of the isolates exhibited resistance to vancomycin, tigecycline, or metronidazole. Furthermore, different toxin types displayed varying anti-microbial characteristics., Conclusions: The strains identified in Chongqing, Southwest China, exhibited high genetic diversity. Enhance full awareness of high-risk patients with HA-CDI infection, particularly those with gastrointestinal and hepatocellular diseases, and emphasize caution in the use of tetracycline and capecitabine. These findings suggest that a potential epidemic of CDI may occur in the future, emphasizing the need for timely monitoring., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Escherichia coli (E. coli) strains, from the gut of animals and humans, harbor wide range of drug resistance genes. A comparative study is conducted on the intestinal E. coli from fecal samples of healthy chicken from China and Sudan in order to monitor the antimicrobial sensitivity pattern. A number of 250 E. coli isolates from chicken farms, including 120 from China and 130 from Sudan, were isolated and identified. All isolates were subjected to susceptibility tests against 10 antibiotics and the distribution of antibiotic resistant genes was confirmed by PCR amplification, involving genes such as ampC, tetA, pKD13, acrA, ermA, ermB, ermC, tetB, mphA, aadA14, aadA1, aac3-1, and aac3- III. Many isolates were found to exhibit resistance against more than one antibiotic. However, the Chinese isolates showed more antibiotics resistance and resistance genes compared to the Sudanese isolates. For better understanding of the multidrug resistance factors, we conducted whole genome analyses of E. coli D107 isolated from China, which revealed that the genome possesses multiple resistance genes including tetracycline, erythromycin, and kanamycin. Furthermore, E. coli D4 isolate from Sudan was more sensitive to antibiotics such as erythromycin, tetracycline, and gentamicin. After analysis by RAST and MAUVE, the two strains showed 89% average nucleotide identity. However, the genomes mostly differed at the number of antibiotics-related genes, as the genome of D107 revealed a considerable number of antibiotics resistance genes such as ermA and mphD which were found to be absent in D4 genome. These outcomes provided confirmation that the poultry farms environment in different countries (China and Sudan) may serve as a potential reservoir of antimicrobial resistance genes and also indicated the evolutionary differences of strains in terms of resistant genes expression. [ABSTRACT FROM AUTHOR]

Antibiotic resistance has become a widely concerned issue due to the huge risk on the ecological environment and human health. China has the highest production and consumption of antibiotics than other countries. Thus, antibiotic resistance genes (ARGs) have been detected in various environmental settings (e.g., surface water, wastewater, sediment) in China. The occurrence of ARGs in these matrixes was summarized and discussed in this review. Sulfonamide resistance genes and tetracycline resistance genes were the most frequently detected ARGs in China. According to the abundance of these two classes of ARGs in the natural environment, sulfonamide resistance genes seem to be more stable than tetracycline resistance genes. Furthermore, the relationships between ARGs and antibiotics, antibiotic resistance bacteria (ARB), heavy metals, and environmental parameters (e.g., pH, organics) were also investigated. Specifically, relative abundance of total ARGs was found to correlate well with concentration of total antibiotics in aqueous phase but not in the solid phase (soil, sediment, sludge, and manure). As for relationship between ARGs and ARB, metals, and environmental parameters in different media, due to complex and variable environment, some exhibit positive correlation, some negative, while others no correlation at all. Three potential risks are discussed in the text: transmission to human, synergistic effect of different ARGs, and variability of ARGs. However, due to the complexity of the environment, more work is needed to establish a quantitative approach of ARG risk assessment, which can provide a theoretical support for the management of antibiotics and the protection of human health. [ABSTRACT FROM AUTHOR]