Ratiometric fluorescence sensing and discrimination of tetracycline analogs by using coumarin-embedded Eu-MOF nanosensor.

As widely used antibiotics, tetracycline residues exist in food and environmental media, which pose certain hidden dangers and negative effects on public health. Therefore, the sensing and discrimination of tetracycline analogs (TCs) have great significance for improving food safety and preventing environmental pollution. Herein, a 7-hydroxycoumarin-3-carboxylic acid-embedded Eu-MOF (HC@Eu-MOF) material was constructed and then developed for the detection of TCs. Upon addition of TCs, the synthesized sensor displays opposite fluorescence changes at two different wavelengths due to the simultaneous presence of the inner filter effect (IFE) and the antenna effect (AE), and achieves a stable ratio signal response within 90 s. In addition, six important tetracycline analogs, including chlortetracycline (CTC), oxytetracycline (OTC), tetracycline (TC), metacycline (MC), doxycycline (DC) and demeclocycline (DMC) can be discriminated with 100 % accuracy through the principal component analysis even in extremely complicated mixtures. Further, a smartphone-assisted portable device was applied for visual sensing of TCs. The as-developed platform possessed the characteristics of simple synthesis, fast response, high sensitivity, and high stability, which further lays a further foundation for the on-site visual detection and discrimination of TCs in real samples.

A high-efficiency and selective fluorescent assay for the detection of tetracyclines.

Tetracyclines (TCs) rank second globally in the use of animal infection therapy and animal husbandry as growth promoters among all antibiotics. However, large amounts of TCs residue in food products and more than 75% of TCs are excreted into the environment, causing adverse effects on the ecological system and human health. It has been challenging to simultaneously realize low-cost, rapid, and highly selective detection of TCs. Here, inspired by the fluorogenic reactions between resorcinol and catecholamines, we find the fluorescence quenching ability of tetracycline (TC) and firstly propose a fluorescent "turn-off" detection of TC using dopamine and 4-fluororesorcinol. The optimal reaction condition for the fluorescent assay is investigated and the optimized probe showed a good limit of detection (LOD of 1.7 µM) and a wide linear range (10 µM to 350 µM). Moreover, this fluorescent assay proved to be an effective tool for detecting TC in river, Sprite, and beer samples, which represent the aquatic environments and food and may contain tetracyclines residues. Finally, the high selectivity of the method for TC has been confirmed by eliminating the interference from common substances. The proposed strategy provides a high-efficiency and selective solution for the detection of TCs in environment and food and the application fields of this fluorescent assay could be further expanded in the future.

[Comparison of efficacy and safety between elacycline and polymyxin for complicated intra-abdominal infections caused by multidrug-resistant bacteria].

Objective: To compare the efficacy and safety of eravacycline and polymyxin drugs in the treatment of multidrug-resistant complicated intra-abdominal infections(cIAI). Methods: The cIAI patients diagnosed or highly suspected of multidrug resistant bacterial infection who received eravacycline treatment at Sir Run Run Shaw Hospital and Shulan (Hangzhou) Hospital from June to August 2023 were prospectively included as the elacycline group. The cIAI patients with cIAI caused by multidrug resistant bacteria who received treatment with polymyxin (B or E) from January 2021 to August 2023 were retrospectively collected. The acute physiology and chronic health scores and age were matched with those of the elacrinid group, and they were included in the polymyxin group. The study mainly analyzed the clinical efficacy, microbial clearance rate, comprehensive efficacy, and safety of the two groups at the end of treatment and discharge. Results: A total of 72 patients with cIAI were included in the study, including 53 males and 19 females, aged (56.0±15.4) years. Among them, there were 28 cases in the eravacycline group and 44 cases in the polymyxin group. There was no statistically significant differences in the baseline, the proportion of patients who used combined drugs, the strains, the infection sites and infection conditions of patients between the two groups(all P>0.05).The clinical efficacy rate at the end of treatment [89.3% (25/28) vs 56.8%(25/44), P=0.004] and discharge [(88.5%(23/26) vs 63.6%,(28/44), P=0.024], microbial clearance rate at the end of treatment [(88.9% (24/27) vs 47.6%(20/42), P=0.001] and discharge [(91.3%(21/23) vs 59.5%(25/42), P=0.007], and overall recovery rate at the end of treatment [(89.3%(25/28) vs 52.3%(23/44), P=0.001] and discharge [(88.5%(23/26) vs 63.6%(28/44), P=0.024] in the erythromycin group were higher than those in the polymyxin drug group. In terms of safety, only 2 cases of mild vasculitis were observed in the eravacycline group. Conclusions: Combined regimens based on eravacycline showed better clinical effect in the treatment of cIAI caused by multidrug-resistant bacteria. The clinical effective rate, microbial clearance rate and comprehensive efficacy were significantly higher than those of polymyxin drugs at the end of treatment and discharge with good safety.

Source apportionment and ecological risk assessment of antibiotics in Dafeng River Basin using PMF and Monte-Carlo simulation.

Antibiotics, prevalent in aquatic ecosystems, pose a grave threat to human health and the ecological well-being. This paper performed a case study on Dafeng River Basin in southern China. Specifically, techniques including positive matrix factorization (PFM) and Monte-Carlo simulation were employed to comprehensively investigate the spatial variations, possible sources, and ecological risks of antibiotics in four groups: sulfonamides (SAs), macrolides (MLs), quinolones (QNs), and tetracyclines (TCs). The major findings were as follows: first, 43 and 39 antibiotics were detected in the surface water and sediments of the basin, respectively, where the respective total content were ND-490.08 ng/L and ND-144.34 µg/kg, and the QNs and TCs were the two dominating groups. Second, the highest antibiotic content in surface water (441.43 ng/L) was observed in the midstream area, whereas the highest concentration in sediments (68.41 µg/kg) was found in the upstream region. Third, the investigation identified five sources of antibiotics discharged to surface water: domestic sewage, agricultural drainage, livestock discharge, sewage treatment plants, and aquaculture; three sources were detected for antibiotics in sediments: aquaculture, sewage treatment plants, and livestock discharge. Fourth, QNs had a significantly higher ecological risk than the other three groups of antibiotics, and livestock discharge (31.4% contribution) and aquaculture (23.4% contribution) were the main sources of risks of antibiotic contamination in Dafeng River Basin. This study is expected to provide some reference for control and risk management of antibiotic pollution in Dafeng River Basin.

New-generation tetracyclines for severe macrolide-resistant Mycoplasma pneumoniae pneumonia in children: a retrospective analysis.

BACKGROUND: Macrolide-resistant Mycoplasma pneumoniae (MRMP) strains are increasingly prevalent, leading to a rise in severe Mycoplasma pneumoniae pneumonia incidence annually, which poses a significant threat to children's health. This study aimed to compare the effectiveness and safety of oral minocycline and doxycycline for the treatment of severe MRMP pneumonia in children. METHODS: This retrospective analysis included children treated for severe MRMP pneumonia at the Pediatric Department of Tongji Hospital, Shanghai, China, between September 2023 and January 2024 using minocycline and doxycycline. The patients were divided into four groups according to treatment: oral doxycycline alone (DOX group), oral minocycline alone (MIN group), oral doxycycline with intravenous glucocorticoids (DOXG group), and oral minocycline with intravenous glucocorticoids (MING group). Student's t-test, Mann-Whitney U test, and χ2 or Fisher's exact tests were used for group comparisons. RESULTS: A total of 165 patients were included in this study: 84 received minocycline, and 81 received doxycycline. The DOX group had higher fever resolution rates within 24, 48, and 72 h compared to the MIN group (63.2% vs. 31.8%, 79.0% vs. 63.6%, and 100% vs. 90.9%, respectively; all p < 0.05). The DOXG group showed higher fever resolution rates within 24 and 48 h than the MING group (92.3% vs. 83.4%, 100% vs. 92.7%, all p > 0.05). There were no statistically significant differences in time to imaging improvement, cough improvement, and disappearance of wet rales between groups, regardless of glucocorticoid combination. The longer the duration of fever prior to tetracycline therapy, the greater the likelihood of hypoxemia (p = 0.039) and a greater than two-fold elevation in the D-dimer level (p = 0.004).Univariate binary logistic regression model analysis revealed that CRP and erythrocyte sedimentation rate at disease onset were associated with defervescence within 24 h after treatment with tetracyclines alone (p = 0.020, p = 0.027), with erythrocyte sedimentation rate also influencing defervescence within 48 h (p = 0.022). CONCLUSION: Doxycycline treatment resulted in a higher rate of defervescence than minocycline. Prompt treatment reduced the probability of pleural effusion, hypoxemia, pulmonary atelectasis, and D-dimer levels > 2 times the reference value.

PhoPQ-mediated lipopolysaccharide modification governs intrinsic resistance to tetracycline and glycylcycline antibiotics in Escherichia coli.

Tetracyclines and glycylcycline are among the important antibiotics used to combat infections caused by multidrug-resistant Gram-negative pathogens. Despite the clinical importance of these antibiotics, their mechanisms of resistance remain unclear. In this study, we elucidated a novel mechanism of resistance to tetracycline and glycylcycline antibiotics via lipopolysaccharide (LPS) modification. Disruption of the Escherichia coli PhoPQ two-component system, which regulates the transcription of various genes involved in magnesium transport and LPS modification, leads to increased susceptibility to tetracycline, minocycline, doxycycline, and tigecycline. These phenotypes are caused by enhanced expression of phosphoethanolamine transferase EptB, which catalyzes the modification of the inner core sugar of LPS. PhoPQ-mediated regulation of EptB expression appears to affect the intracellular transportation of doxycycline. Disruption of EptB increases resistance to tetracycline and glycylcycline antibiotics, whereas the other two phosphoethanolamine transferases, EptA and EptC, that participate in the modification of other LPS residues, are not associated with resistance to tetracyclines and glycylcycline. Overall, our results demonstrated that PhoPQ-mediated modification of a specific residue of LPS by phosphoethanolamine transferase EptB governs intrinsic resistance to tetracycline and glycylcycline antibiotics. IMPORTANCE: Elucidating the resistance mechanisms of clinically important antibiotics helps in maintaining the clinical efficacy of antibiotics and in the prescription of adequate antibiotic therapy. Although tetracycline and glycylcycline antibiotics are clinically important in combating multidrug-resistant Gram-negative bacterial infections, their mechanisms of resistance are not fully understood. Our research demonstrates that the E. coli PhoPQ two-component system affects resistance to tetracycline and glycylcycline antibiotics by controlling the expression of phosphoethanolamine transferase EptB, which catalyzes the modification of the inner core residue of lipopolysaccharide (LPS). Therefore, our findings highlight a novel resistance mechanism to tetracycline and glycylcycline antibiotics and the physiological significance of LPS core modification in E. coli.

P-doped carbon dot nano-probe for inner filter effect-based determination of sarecycline in pharmaceutical dosage form and human plasma.

Based on novel phosphorus-doped carbon dots (PCDs), a simple, quick, and accurate fluorescence probe for sarecycline (SAR) determination has been created. The PCDs were prepared in just five minutes using green, straightforward one-step microwave pyrolysis. To create the PCD probe, sodium phosphate monobasic was utilized as a phosphorus dopant and citric acid as a carbon supply. The proposed synthesis method was energy efficient and yielded CDs with a narrow particle size distribution. Based on inner-filter effect mechanism, the generated PCDs were used as nano-probe for SAR determination. The fluorescence quenching intensity showed a strong linear relationship with SAR concentration in the 3-90-µM range with a detection limit of 0.88 µM. Because there is no surface alteration of the CDs or creation of a covalent bond between SAR and PCDs, the developed approach is quick, easy, inexpensive, and requires less time. The new probe's enhanced sensitivity, broad linear range, and acceptable selectivity made it suitable for SAR measurement in pharmaceutical formulations and spiked human plasma. Most importantly, the Green Analytical Procedure Index (GAPI) and Analytical GREEnness (AGREE) assessments showed that the suggested method was environmentally friendly.

A new parameter for quantitatively characterizing antibiotic hormesis: QSAR construction and joint toxic action judgment.

Antibiotics usually induce the hormetic effects on bacteria, featured by low-dose stimulation and high-dose inhibition, which challenges the central belief in toxicity assessment and environmental risk assessment of antibiotics. However, there are currently no ideal parameters to quantitatively characterize hormesis. In this study, an effective area in hormesis (AH) was developed to quantify the biphasic dose-responses of single antibiotics (sulfonamides (SAs), sulfonamides potentiators (SAPs), and tetracyclines (TCs)) and binary mixtures (SAs-SAPs, SAs-TCs, and SAs-SAs) to the bioluminescence of Aliivibrio fischeri. Using Ebind (the lowest interaction energy between antibiotic and target protein) and Kow (octanol-water partition coefficient) as the structural descriptors, the reliable quantitative structure-activity relationship (QSAR) models were constructed for the AH values of test antibiotics and mixtures. Furthermore, a novel method based on AH was established to judge the joint toxic actions of binary antibiotics, which mainly exhibited synergism. The results also indicated that SAPs (or TCs) contributed more than SAs in the hormetic effects of antibiotic mixtures. This study proposes a new quantitative parameter for characterizing and predicting antibiotic hormesis, and considers hormesis as an integrated whole to reveal the combined effects of antibiotics, which will promote the development of risk evaluation for antibiotics and their mixtures.

Possible omadacycline induce acute pancreatitis: a case report and literature review.

BACKGROUND: Omadacycline is a new generation of tetracycline antibiotics, and its clinical application is increasing. We report the first case of acute pancreatitis possibly induced by omadacycline. CASE PRESENTATION: The patient was admitted to the emergency intensive care unit due to community-acquired pneumonia. The initial treatment consisted of meropenem combined with levofloxacin, and the regimen was subsequently switched to omadacycline combined with cefoperazone/sulbactam due to sputum culture showing carbapenem-resistant Acinetobacter baumannii. Seven days after the administration of omadacycline, abdominal tenderness occurred, and CT scan revealed an enlarged gallbladder with exudation from the pancreatic head. The patient was diagnosed with acute pancreatitis and improved after dis-continuing omadacycline. CONCLUSIONS: Omadacycline, like other tetracycline antibiotics, may cause pancreatitis. Combination medications can be an important factor in this adverse reaction.

Zidovudine in synergistic combination with nitrofurantoin or omadacycline: in vitro and in murine urinary tract or lung infection evaluation against multidrug-resistant Klebsiella pneumoniae.

Limited treatment options and multidrug-resistant (MDR) Klebsiella pneumoniae present a significant therapeutic challenge, underscoring the need for novel approaches. Drug repurposing is a promising tool for augmenting the activity of many antibiotics. This study aimed to identify novel synergistic drug combinations against K. pneumoniae based on drug repurposing. We used the clinically isolated GN 172867 MDR strain of K. pneumoniae to determine the reversal resistance activity of zidovudine (AZT). The combined effects of AZT and various antibiotics, including nitrofurantoin (NIT) and omadacycline (OMC), were examined using the checkerboard method, growth curves, and crystal violet assays to assess biofilms. An in vitro combination activity testing was carried out in 12 isolates of K. pneumoniae. In vivo murine urinary tract and lung infection models were used to evaluate the therapeutic effects of AZT + NIT and AZT + OMC, respectively. The fractional inhibitory concentration index and growth curve demonstrated that AZT synergized with NIT or OMC against K. pneumoniae strains. In addition, AZT + NIT inhibited biofilm formation and cleared mature biofilms. In vivo, compared with untreated GN 172867-infected mice, AZT + NIT and AZT + OMC treatment decreased colony counts in multiple tissues (P < 0.05) and pathological scores in the bladder and kidneys (P < 0.05) and increased the survival rate by 60% (P < 0.05). This study evaluated the combination of AZT and antibiotics to treat drug-resistant K. pneumoniae infections and found novel drug combinations for the treatment of acute urinary tract infections. These findings suggest that AZT may exert significant anti-resistance activity.

Centrifugated lateral flow assay strips based on dual-emission carbon dots modified with europium ions for ratiometric determination and on-site discrimination of tetracyclines in environment.

Due to the serious detrimental impact on human health, antibiotic pollution particularly tetracyclines residues has become a serious problem. Herein, a multiple response fluorescent probe consisted of dual-emission carbon dots and Eu3+ (D-CDs@Eu3+) is designed for the determination and discrimination of tetracyclines (TCs). Specifically, the carboxyl and amidogen group of dual-emission carbon dots (D-CDs) can coordinate with Eu3+ to form the D-CDs@Eu3+. Upon adding TCs, the fluorescence intensities of D-CDs at 405 nm and 495 nm are quenched due to inner filter effect (IFE) and the localization of fluorescence resonance energy transfer (L-FRET) between the D-CDs@Eu3+ and TC. Simultaneously, the D-CDs@Eu3+ may chelate with TCs to enhance the occurrence of antenna effect, while the characteristic peaks of Eu3+ at 590 nm and 615 nm are enhanced. On these bases, the TCs detection is achieved with low detection limits from 46.7 to 72.0 nM. Additionally, through the distinct efficiencies of L-FRET, the discrimination of TCs is achieved. Moreover, a novel centrifugated lateral flow assay strips (CLFASs) device is developed by integrating the D-CDs@Eu3+, lateral flow assay strips and smartphone using RGB variations for TCs detection, achieving remarkable recoveries (98.6-103.7 %) in real samples. Therefore, this CLFASs device provides a reliable approach for the TCs detection, demonstrating potential applications.

Determination of tetracycline residues in potatoes and soil by LC-MS/MS: Method development, validation, and risk assessment.

A method utilizing liquid-liquid extraction (LLE) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and validated according to the Commission Implementing Regulation (CIR) EU 2021/808 for quantifying four tetracyclines (TCs) in potatoes and soil. The method demonstrated recovery values ranging from 70 to 121% and precision (repeatability and within-laboratory reproducibility), with coefficient of variation (CV) values below 18% for all TCs in both matrices. The limits of quantification (LOQs) for the TCs ranged from 0.90 to 1.87 µg/kg in potatoes and from 0.68 to 1.25 µg/kg in soil. The decision limit (CCα) and detection capability (CCß) ranged from 10.4 to 12.3 µg/kg and 11.9 to 14.3 µg/kg, respectively. Analysis of 538 potato and soil samples from Egyptian farms revealed a 13.2% occurrence of TC residues, with a higher frequency in soil (19.33%) than in potatoes (7.06%). Target hazard quotient (THQ) values indicated that TC residues in potatoes do not pose a health risk to Egyptian consumers.

Overlooked interconversion between tetracyclines and their 4-epimers in soil and effects on soil resistome and bacterial community.

With the widespread use of tetracycline antibiotics (TCs) and the application of manure fertilizer in farmland, TCs and their metabolites especially 4-epimers have been heavily detected in agricultural soil. However, existing studies have focused on the residual and environmental behavior of maternal TCs, and few studies have looked at the ecotoxicity of their 4-epimers in soil. In this study, the degradation and interconversion of tetracycline (TC), oxytetracycline (OTC) and their 4-epimers (4-epitetracycline, ETC; 4-epioxytetracycline, OTC) were revealed. Their effects on antibiotic resistance genes (ARGs), mobile genetic elements (MGEs) and bacterial community in soil were also investigated in comparison. The results showed that the 4-epimers could be substantially transformed to their parents and degraded as a whole. The degradation rates of four selected pollutants are followed: TC > OTC > ETC > EOTC. This indicated that when TCs entered the soil, part of TCs transformed into slower-degraded 4-epimers, and these 4-epimers could also be converted back to their antibiotic parents, causing the long-term residue of TCs in soil. When added to the soil alone, TC and OTC significantly promoted the proliferation of most ARGs and MGEs, among them, trb-C, IS1247 and IS1111 were the top three genes in abundance. ETC and EOTC had little effect at the beginning. However, as the 4-epimers continuously converted into their parents after one month of cultivation, ETC and EOTC treatments showed similar promoting effect on ARGs and MGEs, indicating that the effect of ETC and EOTC on soil resistome was lagged and mainly caused by their transformed parents. Nocardioides, unclassified_Rhizobiaceae, norank_Sericytochromatia, Microlunatus, Solirubrobacter and norank_67-14 were the most frequent hosts of ARGs, Most of which belong to the phylum Actinobacteria. Due to their large transformation to TCs, slow degradation rate and potential effects on soil microbes and ARGs, the harm of TCs' 4-epimers on soil ecosystem cannot be ignored.

Utilizing Morphological and Physiological Parameters of Lemna minor for Assessing Tetracyclines' Removal.

Antibiotics with significant environmental toxicity, e.g., tetracyclines (TCs), are often used in large quantities worldwide, with 50-80% of the applied dose ending up in the environment. This study aimed to investigate the effects of exposure to tetracycline hydrochloride (TC) and minocycline hydrochloride (MIN) on L. minor. Our research evaluated the phytotoxicity of the TCs by analyzing plant growth and biomass and evaluating assimilation pigment levels and fluorescence. The research was extended with the ability potential of duckweed as a tool for removing TCs from water/wastewater. The results demonstrated that both TCs influenced Ir, Iy, biomass, and photosynthetic efficiency. The uptake of TC and MIN by duckweed was proportional to the concentration in the growth medium. The TC was absorbed more readily, reaching up to 8.09 mg × g-1 of dry weight (DW) at the highest concentration (19.2 mg × L-1), while MIN reached 6.01 mg × g-1 of DW. As indicated, the consequences of the influence of TC on plants were slightly smaller, in comparison to MIN, while the plants could biosorb this drug, even at the lowest tested concentration. This study has shown that using plants for drug biosorption can be an effective standalone or complementary method for water and wastewater treatment.

Direct evolution of an alkaline fungal laccase to degrade tetracyclines.

A fungal laccase-mediator system capable of high effectively oxidizing tetracyclines under a wide pH range will benefit environmental protection. This study reported a directed evolution of a laccase PIE5 to improve its performance on tetracyclines oxidization at alkaline conditions. Two mutants, namely MutA (D229N/A244V) and MutB (N123A/D229N/A244V) were obtained. Although they shared a similar optimum pH and temperature as PIE5, the two mutants displayed approximately 2- and 5-fold higher specific activity toward the mediators ABTS and guaiacol at pHs 4.0 to 6.5, respectively. Simultaneously, their catalytic efficiency increased by 8.0- and 6.4-fold compared to PIE5. At a pH range of 5-8 and 28 °C, MutA or MutB at a final concentration of 2.5 U·mL-1 degraded 77 % and 81 % of 100 mg·L-1 tetracycline within 10 min, higher than PIE5 (45 %). Furthermore, 0.1 U·mL-1 MutA or MutB completely degraded 100 mg·L-1 chlortetracycline within 6 min in the presence of 0.1 mM ABTS. At pH 8.0, MutA degraded tetracycline and chlortetracycline following the routine pathways were reported previously based on LC-MS analysis.

Heterometallic Eu/Zn-MOF-based ratiometric sensing platform: Highly sensitive fluorescence / second-order scattering identification of tetracycline analogs and its molecular informatization applications.

The traditional preparation method of ratiometric probes faces challenges such as cumbersome preparation and low sensitivity. Thus, there is an urgent need to provide a simple method of preparing a highly sensitive ratiometric probe. Here, Eu3+-doped zinc-based organic framework (Eu/Zn-MOF) was prepared through hydrothermal method for the detection of tetracycline analogs (TCs). Under the same excitation conditions, the probe can simultaneously display valuable fluorescence and second-order scattering signals. The developed probe enabled specific identification and fast detection (1 min) of TCs, including tetracycline, oxytetracycline, doxycycline, and chlortetracycline. The linear detection ranges of tetracycline, oxytetracycline, doxycycline and chlortetracycline were respectively 100 nM - 200 µM, 100 nM - 200 µM, 98 nM - 195 µM, and 97 nM - 291 µM, and the corresponding detection limits were respectively 15.79 nM, 20.83 nM, 15.31 nM, and 28.30 nM. The developed sensor was successfully applied to detect TCs in real samples, and the recovery rate was from 92.54 % to 109.69 % and the relative standard deviation was from 0.04 % to 2.97 %. Moreover, the heterometallic Eu/Zn-MOF was designed as a ratiometric neuron for Boolean logic computing and information encryption based on the specific identification of TCs. As a proof of concept, molecular steganography was successfully employed to encode, store, and conceal information by transforming the specific identification patterns of Eu/Zn-MOF into binary strings. This study is anticipated to advance the application of metal-organic frameworks in logic detection and information security, and bridging the gap between molecular sensors and the realm of information.

Thiadiazol ligand-based laccase-like nanozymes with a high Cu+ ratio for efficient removal of tetracyclines through polymerization.

A promising water treatment technology involves inducing the polymerization of organic pollutants to form corresponding polymers, enabling rapid, efficient, and low CO2 emission removal of these pollutants. However, there is currently limited research on utilizing polymerization treatment technology for removing tetracyclines from water. In this study, we synthesized a laccase-mimic nanozyme (Cu-ATZ) with a high Cu+ ratio using 2-amino-1,3,4-thiadiazole as a ligand inspired by natural laccase. The Cu-ATZ exhibited enhanced resistance to more severe application conditions and improved stability compared to natural laccase, thereby demonstrating a broader range of potential applications. The excellent catalytic properties of Cu-ATZ enabled the nanozyme to be used in the polymerization process to remove tetracyclines from water. In order to simulate actual antibiotic pollution of water bodies, tetracyclines were added to the water from sewage treatment plants. Following Cu-ATZ treatment of the water sample, the chemical oxygen demand (COD) content was found to have decreased by over 80 %. In conclusion, this study presented a novel approach for tetracycline elimination from water.

Omadacycline is active in vitro and in vivo against ciprofloxacin-resistant Bacillus anthracis.

Bacillus anthracis, the causative agent of anthrax, is among the most likely bacterial pathogens to be used in a biological attack. Inhalation anthrax is a serious, life-threatening form of infection, and the mortality from acute inhaled anthrax can approach 100% if not treated early and aggressively. Food and Drug Administration-approved antibiotics indicated for post-exposure prophylaxis (PEP) or treatment of anthrax are limited. This study assessed the in vitro activity and in vivo efficacy of omadacycline and comparators against clinical isolates of B. anthracis, including a ciprofloxacin-resistant isolate. Minimum inhibitory concentrations (MICs) of omadacycline, ciprofloxacin, and doxycycline were determined against animal and human clinical isolates of B. anthracis, including the ciprofloxacin-resistant Ames strain BACr4-2. Mice were challenged with aerosolized BACr4-2 spores, and survival was monitored for 28 days post-challenge. Treatment was initiated 24 h after aerosol challenge and administered for 14 days. Omadacycline demonstrated in vitro activity against 53 B. anthracis isolates with an MIC range of ≤0.008-0.25 µg/mL, and an MIC50/MIC90 of 0.015/0.03 µg/mL. Consistent with this, omadacycline demonstrated in vivo efficacy in a PEP mouse model of inhalation anthrax caused by the Ames BACr4-2 ciprofloxacin-resistant B. anthracis isolate. Omadacycline treatment significantly increased survival compared with the vehicle control group and the ciprofloxacin treatment group. As antibiotic resistance rates continue to rise worldwide, omadacycline may offer an alternative PEP or treatment option against inhalation anthrax, including anthrax caused by antibiotic-resistant B. anthracis.

A MOF-on-MOF heterostructure ratiometric/colorimetric dual-mode fluorescence sensor based on support vector machine for detecting tetracyclines in animal-derived foods.

The misuse of tetracyclines in livestock production poses significant health risks. Thus, establishing convenient detection methods to replace complex laboratory tests for food safety is crucial. In this study, a heterostructure Zn-BTC/IRMOF-3 (denoted as ZBI) asynchronous response fluorescence sensor was developed for the qualitative and quantitative detection of tetracyclines in foods. The ZBI solution exhibited blue fluorescence under UV excitation; upon the introduction of tetracyclines, ZBI selectively recognized the tetracycline molecules through electron transfer, π-π stacking, and chelation, resulting in blue fluorescence quenching and green fluorescence enhancement. The ZBI sensor for tetracycline detection achieved recovery rates ranging from 93.91 to 111.91% in food samples, with a detection limit of as low as 0.086 µmol/L. Lastly, a portable sensing device using support vector classifier was constructed for detecting tetracyclines in real-life scenarios. Our findings introduce a new approach for fabricating fluorescence sensors and offer a novel method for detecting tetracyclines.