Selective adsorption of tetracycline by β-CD-immobilized sodium alginate aerogel coupled with ultrafiltration for reclaimed water

In this work,a novel composite material based on β-cyclodextrin-immobilized sodium alginate aerogel(β-CD/NaAlg) was developed utilizing cross-linker of epichlorohydrin and applied as an adsorbent to remove tetracycline antibiotics from reclaimed wastewater.A series of characterizations were utilized to confirm the successful synthesis of the adsorbent and this β-CD/NaAlg presented a three-dimensional network at the nanoscale or microscale.Under optimal conditions(pH=4,t=8 h,β-CD:NaAlg=9,adsorbent dosage = 1.5 g·L-1),the maximum removal rate of β-CD/NaAlg to tetracycline was 70%.The adsorption behavior of tetracycline on β-CD/NaAlg conformed to the Freundlich isotherm model(R2=0.9977) and the pseudo-second-order kinetic model(R^(2)=0.9993).Moreover,the adsorbent still removed 55.3% of tetracycline after five cycles.Specially,the adsorbent was integrated with ultrafiltration to adsorb tetracycline antibiotics from simulated reclaimed wastewater,and the removal rate of tetracycline reached 78.9% within 2 h.The existence of Cr(Ⅵ) had a negligible impact on tetracycline removal,while the presence of humic acid exhibited a promoting effect.The possible adsorption mechanisms were also elucidated through X-ray photoelectron spectroscopy and density functional theory analysis.In summary,β-CD/NaAlg represents an environmentally friendly,efficient,and sustainable adsorbent for removing tetracycline antibiotics from reclaimed water.

Development of a Simple Extraction Method for Tetracycline Analogues from Bovine Milk

Tetracycline and analogues are among the most used antibiotics in the dairy industry. Besides the therapeutic uses, tetracyclines are often incorporated into livestock feed as growth promoters. A considerable amount of antibiotics is released unaltered through milk from dairy animals. The presence of antibiotic residues in milk and their subsequent consumption can lead to potential health impacts, including cancer, hypersensitivity reactions, and the development of antibiotic resistance. Thus, it is important to monitor residual levels of tetracyclines in milk. The purpose of this study is to develop a quick and simple method for simultaneously extracting five tetracycline analogues from bovine milk. Specifically, five tetracycline analogues: Chlortetracycline (CTC), demeclocycline (DEM), doxycycline (DC), minocycline (MC), and tetracycline (TC) were simultaneously extracted from milk using trifluoroacetic acid. Subsequently, the extracted analogues were separated by reverse-phase high-performance liquid chromatography (RP-HPLC) and detected at 355 nm using UV/Vis. Calibration curves for all five tetracycline analogues show excellent linearity (r2 value > 0.99). Percent recovery for MC, TC, DEM, CTC, and DC were: 31.88%, 96.91%, 151.29, 99.20%, and 85.58% respectively. The developed extraction method has good precision (RSD < 9.9% for 4 of the 5 analogues). The developed method with minimal sample preparation and pretreatment has the potential to serve as an initial screening test.

Rifaximin discontinuation during broad-spectrum antibiotic treatment in critically ill patients with hepatic encephalopathy

Hepatic encephalopathy(HE)is one of the main complications of cirrhosis,characterized by a wide spectrum of neuropsychiatric alterations that lead to an increase in mortality,morbidity and recurrent hospitalizations.Due to the central role in HE pathogenesis of ammonia and other neurotoxins primarily produced by the gut microbiota,the main therapeutic approaches for the treatment of HE are based on the modulation of the gut microbiota.Rifaximin is a non-absorbable broad-spectrum antibiotic,that is effective against ammonia-producing grampositive,gram-negative,and anaerobic species,approved for the treatment of HE in secondary prophylaxis.The chronic administration of rifaximin in this setting is associated with a lower risk of HE recurrence and mortality,while the role of rifaximin for the treatment of an overt-HE episode in inpatients is still unclear.Limited data exist about the coadministration of rifaximin and broad-spectrum antibiotics commonly used to treat concomitant infections,as patients receiving or recently treated with antibiotics were frequently excluded from clinical trials.In this editorial we comment on the article by Ward et al published in the recent issue of the World Journal of Hepatology.It is a single center,retrospective,quasiexperimental,pharmacist-driven protocol,with the aim to evaluate the feasibility and safety of rifaximin discontinuation in critically ill patients with HE and chronic liver disease receiving broad-spectrum antibiotic therapies in intensive care units.The study revealed no differences between the protocol and control group in terms of primary outcome(days alive and free of delirium and coma to day 14)and secondary outcomes which include:Intensive care mortality,intensive care length of stay,intravenous vasopressor requirement changes and adverse effects rate.Therefore,rifaximin discontinuation during broad-spectrum antibiotic therapy does not appear to negatively impact the clinical status of critically ill liver patients,with a similar safety profile and significant cost savings,as compared to the coadministration of rifaximin and broad-spectrum antibiotics.In agreement with Ward et al,a recently published double-blind,randomized controlled trial provided additional evidence to support the feasibility of withholding rifaximin during broad-spectrum antibiotic therapy in critically ill cirrhotic patients.However,given the limitations of these studies,further multicentric and prospective clinical trials,enrolling a larger sample of non-critically ill patients,are needed to better establish the role of rifaximin in this setting.

Can rifaximin for hepatic encephalopathy be discontinued during broad-spectrum antibiotic treatment?

Hepatic encephalopathy(HE)is a formidable complication in patients with decompensated cirrhosis,often necessitating the administration of rifaximin(RFX)for effective management.RFX,is a gut-restricted,poorly-absorbable oral rifamycin derived antibiotic that can be used in addition to lactulose for the secondary prophylaxis of HE.It has shown notable reductions in infection,hospital readmission,duration of hospital stay,and mortality.However,limited data exist about the concurrent use of RFX with broad-spectrum antibiotics,because the patients are typically excluded from studies assessing RFX efficacy in HE.A pharmacist-driven quasi-experimental pilot study was done to address this gap.They argue against the necessity of RFX in HE during broad-spectrum antibiotic treatment,particularly in critically ill patients in intensive care unit(ICU).The potential for safe RFX discontinuation without adverse effects is clearly illuminated and valuable insight into the optimization of therapeutic strategies is offered.The findings also indicate that RFX discontinuation during broadspectrum antibiotic therapy was not associated with higher rates of delirium or coma,and this result remained robust after adjustment in multivariate analysis.Furthermore,rates of other secondary clinical and safety outcomes,including ICU mortality and 48-hour changes in vasopressor requirements,were comparable.However,since the activity of RFX is mainly confined to the modulation of gut microbiota,its potential utility in patients undergoing extensive systemic antibiotic therapy is debatable,given the overlapping antibiotic activity.Further,this suggests that the action of RFX on HE is class-specific(related to its activity on gut microbiota),rather than drug-specific.A recent double-blind randomized controlled(ARiE)trial provided further evidence-based support for RFX withdrawal in critically ill cirrhotic ICU patients receiving broad-spectrum antibiotics.Both studies prompt further discussion about optimal therapeutic strategy for patients facing the dual challenge of HE and systemic infections.Despite these compelling results,both studies have limitations.A prospective,multi-center evaluation of a larger sample,with placebo control,and comprehensive neurologic evaluation of HE is warranted.It should include an exploration of longer-term outcome and the impact of this protocol in non-critically ill liver disease patients.

Resistance of Helicobacter pylori to antibiotics from 2000 to 2009 in Shanghai

AIM: To investigate the resistance of Helicobacter pylori (H. pylori ) to 6 commonly used antibiotics from 2000 to 2009 in Shanghai. METHODS: A total of 293 H. pylori strains were collected from 2000 to 2009 in Shanghai and tested for their susceptibility to metronidazole, clarithromycin, amoxicillin, furazolidone, levofloxacin and tetracycline using agar dilution. RESULTS: The resistant rates of H. pylori to clarithromycin (8.6%, 9.0% and 20.7%) and levofloxacin (10.3%, 24.0% and 32.5%) increased from 2000 to 2009 in Shanghai. The resistant rate of H. pylori to metronidazole remained stable (40%-50%). Only one strain of H. pylori isolated in 2005 was resistant to tetracycline. All strains were sensitive to amoxicillin and furazolidone.The resistant rate of H. pylori to antibiotics was not related with the sex, age and clinical outcome of patients. CONCLUSION: Resistance of H. pylori to antibiotics plays an important role in making treatment strategies against H. pylori -associated diseases.

Preparation of high selective molecularly imprinted polymers for tetracycline by precipitation polymerization

High selective molecularly imprinted polymers （MIPs） for tetracycline have been prepared by precipitation polymerization. Effects of monomer and solvent, the ratio of monomer and template and the characterization of the polymer were investigated by frontal chromatography and selectivity experiment. The results clearly indicated that the polymer, which had the highest molecular recognition abilities for tetracycline antibiotics, had been received.

Effects of anaerobic composting on tetracycline degradation in swine manure

Oxytetracycline(OTC) and tetracycline(TC) are the most common TC antibiotics used in human and veterinary medicine.Residual amounts of these antibiotics in manure pose a potential threat to public and ecological health as a result of the potential for them to be released to the environment following land application of manure from animals treated with antibiotics.We investigated the degradation of OTC and TC during anaerobic composting.We tested the effects of temperature and antibiotic concentration on degradation rates in a control and in manure spiked with TCs.We examined changes in p H,biological degradation material(BDM),and moisture corresponding with antibiotic degradation of TCs in the swine manure.Results showed that the OTC and TC concentrations decreased by between 68.54% and 95.50% in all nine treatments following 14 days of anaerobic composting,and the highest removal ef ficiencies were observed at an incubation temperature of 55°C and initial concentrations of 10.36 μg·g^(-1),and 5.96 μg·g^(-1) of OTC and TC,respectively,which were degraded by 95.50%,and 90.06%.During composting at 55 °C and at added concentrations of 5 μg·g^(-1),OTC decreased rapidly,and the time required for50% and 90% degradation was 4.1 and 9.8 days,respectively;for TC,these values were 4.4 and 14.0 days,respectively.Removal ef ficiencies for all TCs correlated well with moisture content of the manure.These results show that composting may be a practical and useful means to reduce concentrations of OTC and TC in swine manure prior to its land application.

Green remediation of tetracyclines in soil-water systems

The presence of tetracyclines in soil and surface water is an emerging concern. The present study was undertaken to investigate remediation of tetracylines (tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC)) from aqueous solution using vetiver grass, water lettuce, and sunflower and root exudates of water lettuce, sunflower and from soil by tomato, Indian mustard and carrot plant. The data of this study denote that vetiver grass, water lettuce, sunflower remedy tetracyclines from water. The remediation % after 63 days of treatment was 87-61 for TC;88-68 for OTC and 87-68 for CTC. The remediation of tetracyclines at lower concentration of antibiotics in presence of root exudates of water lettuce and sunflower was more than 99% and remediation was faster than water lettuce or sunflower. The remediation of tetracyclines from aqueous solution may be due to oxidation of-OH group(s) of tetracycline through a process that is thought to involve reactive oxygen intermediates and/or role of peroxidase enzyme. The plant crops viz., tomato, Indian mustard and carrot can remedy 41%-72% of amended tetracyclines. The maximum bioaccumulation of TC and CTC was in Indian mustard and OTC was maximally bioaccumulated in tomato.

Plasma-catalytic degradation of tetracycline hydrochloride over Mn/γ-Al2O3 catalysts in a dielectric barrier discharge reactor

A coaxial dielectric barrier discharge (DBD) reactor was used for plasma-catalytic degradation of tetracycline hydrochloride over a series of Mn/γ-Al2O3 catalysts prepared by the incipient wetness impregnation method.The combination of plasma and the Mn/γ-Al2O3 catalysts significantly enhanced the degradation efficiency of tetracycline hydrochloride compared to the plasma process alone,with the 10% Mn/γ-Al2O3 catalyst exhibiting the best tetracycline hydrochloride degradation efficiency.A maximum degradation efficiency of 99.3% can be achieved after 5 min oxidation and a discharge power of 1.3 W,with only 69.7% by a single plasma process.The highest energy yield of the plasma-catalytic process is 91.7 g kWh-1.Probable reaction mechanisms of the plasma-catalytic removal of tetracycline hydrochloride were also proposed.

Determination of Tetracycline and Oxytetracycline Residues in Honey by High Performance Liquid Chromatography

Honey is being used as a pure natural and as an ingredient in many foods, pharmaceuticals and cosmetics than ever before, so honey testing has become essential to maintain its healthful characteristics and protect public health. Tetracyclines （TCs） are used for the treatment or prevention of American and European foul broad in bee colonies which are caused especially by two species of bacteria--Paenibacillus larvae and Melissococcus pluton. The present study aimed to determine the tetracycline residues in different types of local and imported honey. The reversed-phase high performance liquid chromatography （HPLC） with ultraviolet detection （UV） was used. Tetracycline and oxytetracycline were extracted from honey with 0.01 M sodium succinate buffer. Of the examined samples, 31.25% and 12.50% had these oxytetracycline and tetracycline residues, respectively. It was observed that all the samples studied have been reported residues of tetracycline and oxytetracycline more than international standards of maximum residue limit （MRLs）.

Investigation on the Veterinary Antibiotics Contamination in Groundwater with SPE-LC/MS/MS

[Objective]The aim is to provide data support for the prevention and control of pollution of exogenous chemical in pig breeding industry.[Methods]Solid-phase extraction（SPE）and tandem mass（LC-MS/MS）were used for determining four classes（tetracyclines,quinolones,macrolides and sulfonamides）of 10 common veterinary antibiotics in groundwater of an important pig breeding base in the Yangtze River Delta region of China.[Results]Results revealed the total concentration of the ten antibiotics in urban rivers ranged from 20.1 ng /L to 61.2 ng /L.The highest proportion was taken by tetracyclines,account for 95%,the concentration was up to 44.0 ng /L.Quinolones shared the second largest proportion of total concentration,about 29%,the concentration was up to 21.6 ng /L,while concentration of sulfonamides and macrolides were respectively below 2.7 ng /L and 6.3 ng /L.The highest total concentration of the ten antibiotics in rural rivers was up to 467 ng /L,60% of which was shared by tetracyclines,the highest concentration of tetracyclines was 253 ng /L.Sulfonamides share 20% of the total concentration,the highest concentration of it was 165 ng /L.The highest concentration of macrolides and quinolones was 14.6 ng /L and 14.5 ng /L,respectively.[Conclusion] Antibiotics＇ pollution in town rivers is more serious than urban rivers＇ pollution caused by antibiotics.

Elaborate Design of Two Novel Fluorescent Zinc-based Metal-Organic Frameworks for Highly Efficient Tetracycline Antibiotics Detection

The abuse of tetracycline antibiotics has caused great harm to human health and ecosystems.Developing inexpensive,convenient and sensitive methods for the detection of tetracycline antibiotics is highly desirable.Herein,based on the H_(4)ddp ligand[H_(4)ddp=3-(3,5-dicarboxyphenyl)pyridine-2,6-dicarboxylic acid],two novel zinc-based metal-organic frameworks(MOFs){[Zn_(3)(ddp)_(2)(H_(2)O)_(4)]·3H_(2)O}n(Zn1-ddp)and{[Zn_(3)(ddp)_(2)(H_(2)O)_(4)]·3H_(2)O}n(Zn2-ddp)were successfully designed by delicate structural regulation.Both Zn1-ddp and Zn2-ddp exhibited excellent water and chemical stability and showed excellent fluorescence quenching performance for tetracycline antibiotics.Notably,the more advanced framework structure and better fluorescent performance make Zn1-ddp more sensitive than Zn2-ddp in fluorescent detection with a detection limit of 0.29µmol/L for tetracycline(TC),0.09µmol/L for doxycycline(DOX),0.10µmol/L for minocycline(MIN)and metacycline(MEL),0.19µmol/L for chlortetracycline(CTC),and 0.67µmol/L for oxytetracycline(OTC)among tetracycline antibiotics.The fluorescence quenching mechanism of Zn1-ddp and Zn2-ddp for tetracycline antibiotics detection was deeply investigated.The reasons for the superior detection performance of Zn1-ddp over Zn2-ddp were also analyzed in depth through Fourier transform infrared spectrophotometry(FTIR),X-ray photoelectron spectroscopy(XPS)analysis and framework structure analysis.The developed method opens up a new perspective for antibiotics detection based on zinc-based MOFs.

Applying an AIE type fluorescent probe in the detection of tetracycline antibiotics

The typical representative TPB(tetraphenyl-1,3-butadiene)molecule with AIE effect was used as a fluorescent probe,and the specific recognition of tetracycline antibiotics was achieved through the comparison of the experimental results of the quenching of TPB by nine antibiotics of different types,which indicated that tetracycline antibiotics were found to quench TPB to the greatest extent,while the quenching of other antibiotics(e.q.chloramphenicol,aminoglycoside,sulfonamides,and quinolone)was not obvious.Then the quantitative relationship between the concentration of antibiotic solution and the effect of fluorescence quench was investigated by taking oxytetracycline among tetracycline antibiotics as an example,and the detection limit was calculated.Finally,it was found that the UV absorption spectra of tetracycline hydrochloride and the fluorescence excitation spectra of TPB had high overlap,while the overlap between the UV absorption spectra of other antibiotics,such as sulfadimethoxine,and the fluorescence laser spectrum of TPB was low,which fulfilled the fluorescence internal filtering effect.The fluorescence probe has stable properties,low cost and strong anti-interference ability,which makes the method more valuable in the practical detection of tetracycline.This study indicates great potent in the detection of antibiotics.

Mechanisms of Helicobacter pylori antibiotic resistance:An updated appraisal

Helicobacter pylori(H. pylori) antibiotic resistance is the main factor affecting the efficacy of the current eradicating therapies. The aim of this editorial is to report on the recent information about the mechanisms accounting for the resistance to the different antibiotics currently utilized in H. pylori eradicating treatments. Different mechanisms of resistance to clarithromycin,metronidazole,quinolones,amoxicillin and tetracycline are accurately detailed(point mutations,redox intracellular potential,pump efflux systems,membrane permeability) on the basis of the most recent data available from the literature. The next hope for the future is that by improving the knowledge of resistance mechanisms,the elaboration of rational and efficacious associations for the treatment of the infection will be possible. Another auspicious progress might be the possibility of a cheap,feasible and reliable laboratory test to predict the outcome of a therapeutic scheme.

A new Eu-MOF for ratiometrically fluorescent detection toward quinolone antibiotics and selective detection toward tetracycline antibiotics

Development of new self-calibrating fluorescent sensing methods has been a popular research field with the aim of protecting the human health and environment sustainability. In this work, a novel Eu-based metal organic framework(MOF) Eu(2,6-NDC)(COO)(BUC-88) was developed by employing 2,6-NDC(2,6-naphthalenedicarboxylic acid) as bridging ligands. BUC-88 performed different sensing process toward quinolone antibiotics and tetracyclines antibiotics in terms of fluorescence intensity and color. BUC-88exhibited excellent selectivity and sensitivity detection property toward enrofloxacin(ENR), norfloxacin(NOR) and ciprofloxacin(CIP) over other Pharmaceutical and Personal Care Products(PPCPs), accomplishing the detection limit of 0.12 μmol/L, 0.52 μmol/L, 0.75 μmol/L, respectively. Notably, BUC-88 acted as an excellent fluorescence sensor for tetracyclines antibiotics with fast response time(less than 1 s), high selectivity and sensitivity(LODs = 0.08 μmol/L). The fluorescent detection method was successfully used for visual and ultrasensitive detection of ENR, NOR, CIP and tetracycline hydrochloride(TC) in lake water with satisfied recovery from 99.75% to 102.30%. Finally, the photoinduced electron transfer and the competitive absorption of ultraviolet light are the main mechanisms for sensitive detection toward quinolone antibiotics and tetracyclines antibiotics.

Preparation of hydrophilic molecularly imprinted polymers for tetracycline antibiotics recognition

Hydrophilic molecularly imprinted polymers（MIPs） were prepared using tetracycline as template,methacrylic acid as monomer and glycidilmethacrylate as pro-hydrophilic co-monomer.Compared with common MIPs,the imprinting effect and adsorption amounts of hydrophilic MIPs for tetracycline（TC） were greatly improved in water media.Furthermore,the electrochemical sensor fabricated by modifying hydrophilic MIPs on glassy carbon electrode was developed for the determination of TC in foodstuff samples.

Fluorescence enhancing by alkaline degradation of tetracycline antibiotics and its application

Tetracycline antibiotics could be degraded after being beated in boiling-water bath in alkaline solution (in KOH medium).The fluorescence excitation and emission wavelengths of the degradation products changed and the fluorescence intensity increased by 5-190 folds as compared with that of antibiotics themselves It was considered that there occurred a nucleophilic ring rupture reaction to form the degradation products with lactome structure The mteraction of the lone pair electrons of oxygen on the degradation products with the conjugated π electrons induced the in crease of the delocalization for the conjugated electron system in the molecule and thus enhanced the fluorescence intensity.

Effects of rearing system and antibiotic treatment on immune function,gut microbiota and metabolites of broiler chickens

Background:In China,cage systems with a high space utilization have gradually replaced ground litter systems,but the disease incidence of chickens in cages is higher.Broilers in the ground litter pens may be stimulated by more environmental microbes during the growth process and show strong immune function and status,but knowledge of which microbes and their metabolites play an immunomodulatory role is still limited.This study aimed to explore the differences and correlations in the immune function,gut microbiota and metabolites and the importance of gut microbiota of broilers raised in cages and ground litter pens.Methods:The experiment involved a 2×2 factorial arrangement,with rearing systems(cages or ground litter pens)and antibiotic treatment(with or without broad-spectrum antibiotics in drinking water)as factors.Results:The results showed that,compared with the cage group,the ground litter broilers had stronger nonspecific immune function(Macrophages%and NO in blood),humoral immune function(IgG in blood,LPS stimulation index in ileum)and cellular immune function(T%,Tc%,ConA stimulation index and cytokines in blood).Antibiotic(ABX)treat-ment significantly reduced nonspecific immune function(Macrophages%and NO in blood,iNOS and Mucin2 mRNA expression in ileum),humoral immune function(IgG in blood and sIgA in ileum)and cellular immune function(T%and cytokines in blood,Th and Tc ratio,TLRs and cytokines mRNA expression in ileum).Furthermore,the ground litter broil-ers had higherαdiversity of microbiota in ileum.The relative abundance of Staphylococcus,Jeotgalicoccus,Jeotgalibaca and Pediococcus in the ileum of ground litter broilers were higher.ABX treatment significantly reduced theαdiversity of ileal microbiota,with less Chloroplast and Mitochondria.In addition,the levels of acetic acid,isobutyric acid,kynurenic acid and allolithocholic acid in the ileum of ground litter broilers were higher.Spearman correlation analysis showed that Jeotgalibaca,Pediococcus,acetic acid,kynurenic acid and allolithocholic acid were related to the immune function.Conclusions:There were more potential pathogens,litter breeding bacteria,short-chain fatty acids,kynurenine,allolithocholic acid and tryptophan metabolites in the ileum of broilers in ground litter pens,which may be the reason for its stronger immune function and status.

氧化石墨烯纳米颗粒对抗生素类污染物吸附特征及影响因素

本文通过吸附动力学和吸附等温线探究了氧化石墨烯(GO)纳米颗粒对3种典型的四环素类抗生素(即四环素(TC)、土霉素(OTC)和金霉素(CTC))吸附特征.结果表明,伪二级动力学模型可以很好的拟合吸附动力学的结果,吸附速率可能受化学吸附控制.吸附等温线的结果显示GO对3种抗生素均有较高的吸附能力,且吸附能力依次为:CTC>OTC>TC.这主要是由于四环素类抗生素可以通过π-π作用、阳离子-π键、疏水作用以及静电作用等机制与GO产生结合.此外,四环素类抗生素在GO上的吸附行为与背景溶液的水化学条件(如pH、离子强度和二价金属离子)密切相关.总体来讲,由于静电斥力的增强,抗生素在GO上的吸附量随着背景溶液pH值的升高或离子强度(NaCl)的增加而降低,这主要是由于静电引力和吸附点位的减少所致;二价阳离子(Cu^(2+))可以通过表面桥连作用,显著促进抗生素在GO上的吸附.本研究结果清楚地表明抗生素本身的化学性质和背景溶液的水化学条件在GO去除抗生素的过程起着重要作用.

两种四环素类抗生素单一及复合污染对农田土壤理化性质和土壤酶活性的影响

多数农业用地土壤中抗生素含量在μg·kg^(-1)水平,而μg·kg^(-1)水平抗生素对土壤质量影响的研究较少,因此开展0(CK)、10、100和500μg·kg^(-1)土霉素(OTC)和四环素(TC)的单一及复合污染对土壤理化性质和酶活性的影响研究。结果表明:(1)与CK相比,两种抗生素单一处理土壤pH均显著增加,速效磷(OP)含量均显著降低,且TC处理对pH的增长率和对OP的抑制率均显著高于OTC处理,仅500μg·kg^(-1)TC处理可溶性盐显著降低;单一OTC处理OP含量显著降低,有机质(OM)含量增加,多酚氧化酶(PPO)、脲酶(URE)和蔗糖酶(SUC)活性均显著降低;单一TC处理OP、OM和有效氮(AN)含量均显著降低,PPO和SUC活性均显著下降。(2)在单一OTC处理中加入低含量TC能在一定程度上缓解OTC对土壤的毒害,以10μg·kg^(-1)TC+10μg·kg^(-1)OTC处理综合缓解效果为最佳;而加入较高含量TC则增大OTC对土壤的毒性,且毒性随着OTC含量增加呈上升趋势,以500μg·kg^(-1)TC+500μg·kg^(-1)OTC处理毒性最大;各复合处理组PPO活性均被显著抑制,仅500μg·kg^(-1)TC+OTC复合处理URE活性被显著抑制。(3)土壤理化因子与土壤酶活性密切相关,pH是抑制土壤酶活性的关键因子。综上所述,在μg·kg^(-1)含量水平,单一抗生素处理TC毒性整体高于OTC;低、高含量TC与OTC复合处理分别表现为拮抗作用和协同抑制效应。