Vibrio alginolyticus PEPCK Mediates Florfenicol Resistance through Lysine Succinylation Modification.

Protein succinylation modification is a common post-translational modification (PTM) that plays an important role in bacterial metabolic regulation. In this study, quantitative analysis was conducted on the succinylated proteome of wild-type and florfenicol-resistant Vibrio alginolyticus to investigate the mechanism of succinylation regulating antibiotic resistance. Bioinformatic analysis showed that the differentially succinylated proteins were mainly enriched in energy metabolism, and it was found that the succinylation level of phosphoenolpyruvate carboxyl kinase (PEPCK) was highly expressed in the florfenicol-resistant strain. Site-directed mutagenesis was used to mutate the lysine (K) at the succinylation site of PEPCK to glutamic acid (E) and arginine (R), respectively, to investigate the function of lysine succinylation of PEPCK in the florfenicol resistance of V. alginolyticus. The detection of site-directed mutagenesis strain viability under florfenicol revealed that the survival rate of the E mutant was significantly higher than that of the R mutant and wild type, indicating that succinylation modification of PEPCK protein may affect the resistance of V. alginolyticus to florfenicol. This study indicates the important role of PEPCK during V. alginolyticus antibiotic-resistance evolution and provides a theoretical basis for the prevention and control of vibriosis and the development of new antibiotics.

Detection and adsorption of florfenicol in milk using bifunctional carbon dot-doped molecularly imprinted polymers.

Detection of florfenicol (FF) residues in animal-derived foods, as one of the most widely used antibiotics, is critically important to food safety. The fluorescent molecularly imprinted polymer (MIP) was synthesized by surface-initiated atom transfer radical polymerization technique with poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) microspheres, 4-vinylpyridine, ethylene glycol dimethacrylate, and FF as the matrix, functional monomer, crosslinker, and template molecule, respectively. Meanwhile, N-S co-doped carbon dot (CD) was synthesized with triammonium citrate and thiourea as precursors under microwave irradiation at 400 W for 2.5 min and then integrated into FF-MIP to obtain CD@FF-MIP. For comparison, non-imprinted polymer (NIP) without FF was also prepared. The adsorption capacity of CD@FF-MIP to FF reached 53.1 mg g-1, which was higher than that of FF-MIP (34.7 mg g-1), whereas the adsorption capacity of NIP was only 17.3 mg g-1. The adsorption equilibrium of three materials was reached within 50 min. Particularly, CD@FF-MIP exhibited an excellent fluorescence quenching response to FF in the concentration range of 3-50 µmol L-1. As a result, CD@FF-MIP was successfully utilized to extract FF in milk samples, which were analyzed by high-performance liquid chromatography. The standard recoveries were 95.8%-98.2%, and the relative standard deviation was 1.6%-4.2%. The method showed the advantages of simple operation, high sensitivity, excellent selectivity, and low cost, and also demonstrated a great application prospect in food detection.

Long-term exposure to lead nitrate and zinc sulfate Nile tilapia impact the Aeromonas hydrophila treatment.

BACKGROUND: Pollution with heavy metals (HMs) is time- and concentration-dependent. Lead and zinc pollute the aquatic environment, causing severe health issues in aquatic animals. MATERIALS AND METHODS: Nile tilapia, the predominant cultured fish in Egypt, were experimentally exposed to 10% of LC50 of lead nitrate (PbNO3) and zinc sulfate (ZnSO4). Samples were collected in three different periods, 4, 6, and 8 weeks, in addition to a trial to treat the experimental fish infected with Aeromonas hydrophila, with an antibiotic (florfenicol). RESULTS: Liver enzymes were linearly upsurged in a time-dependent manner in response to HMs exposure. ALT was 92.1 IU/l and AST was 82.53 IU/l after eight weeks. In the eighth week of the HMs exposure, in the hepatic tissue, the levels of glutathione peroxidase (GPx), catalase (CAT), and metallothionein (MT) were increased to 117.8 U/mg prot, 72.2 U/mg prot, and 154.5 U/mg prot, respectively. On exposure to HMs, gene expressions of some cytokines were linearly downregulated in a time-dependent manner compared to the control. After four weeks of exposure to the HMs, the oxidative burst activity (OBA) of immune cells was decreased compared to the control 9.33 and 10.3 cells, respectively. Meanwhile, the serum bactericidal activity (SBA) significantly declined to 18.5% compared to the control 32.6% after eight weeks of exposure. Clinical signs of A. hydrophila infection were exaggerated in polluted fish, with a mortality rate (MR) of 100%. The re-isolation rate of A. hydrophila was decreased in fish treated with florfenicol regardless of the pollution impacts after eight weeks of HMs exposure. CONCLUSION: It could be concluded that the immune suppression and oxidative stress resulting from exposure to HMs are time-dependent. Clinical signs and post-mortem lesions in polluted fish infected with A. hydrophila were prominent. Infected-Nile tilapia had weak responses to florfenicol treatment due to HMs exposure.

A review on the antibiotic florfenicol: Occurrence, environmental fate, effects, and health risks.

Florfenicol, as a replacement for chloramphenicol, can tightly bind to the A site of the 23S rRNA in the 50S subunit of the 70S ribosome, thereby inhibiting protein synthesis and bacterial proliferation. Due to the widespread use in aquaculture and veterinary medicine, florfenicol has been detected in the aquatic environment worldwide. Concerns over the effects and health risks of florfenicol on target and non-target organisms have been raised in recent years. Although the ecotoxicity of florfenicol has been widely reported in different species, no attempt has been made to review the current research progress of florfenicol toxicity, hormesis, and its health risks posed to biota. In this study, a comprehensive literature review was conducted to summarize the effects of florfenicol on various organisms including bacteria, algae, invertebrates, fishes, birds, and mammals. The generation of antibiotic resistant bacteria and spread antibiotic resistant genes, closely associated with hormesis, are pressing environmental health issues stemming from overuse or misuse of antibiotics including florfenicol. Exposure to florfenicol at µg/L-mg/L induced hormetic effects in several algal species, and chromoplasts might serve as a target for florfenicol-induced effects; however, the underlying molecular mechanisms are completely lacking. Exposure to high levels (mg/L) of florfenicol modified the xenobiotic metabolism, antioxidant systems, and energy metabolism, resulting in hepatotoxicity, renal toxicity, immunotoxicity, developmental toxicity, reproductive toxicity, obesogenic effects, and hormesis in different animal species. Mitochondria and the associated energy metabolism are suggested to be the primary targets for florfenicol toxicity in animals, albeit further in-depth investigations are warranted for revealing the long-term effects (e.g., whole-life-cycle impacts, multigenerational effects) of florfenicol, especially at environmental levels, and the underlying mechanisms. This will facilitate the evaluation of potential hormetic effects and construction of adverse outcome pathways for environmental risk assessment and regulation of florfenicol.

Effect of UV pretreatment on the source control of floR during subsequent biotreatment of florfenicol wastewater.

UV photolysis has been recommended as an alternative pretreatment method for the elimination of antibacterial activity of antibiotics against the indicator strain, but the pretreated antibiotic intermediates might not lose their potential to induce antibiotic resistance genes (ARGs) proliferation during subsequent biotreatment processes. The presence of florfenicol (FLO) in wastewater seriously inhibits the metabolic performance of anaerobic sludge microorganisms, especially the positive correlation between UV irradiation doses and ATP content, while it did not significantly affect the organics utilization ability and protein biosynthetic process of aerobic microorganisms. After sufficient UV pretreatment, the relative abundances of floR from genomic or plasmid DNA in subsequent aerobic and anaerobic biotreatment processes both decreased by two orders of magnitude, maintained at the level of the groups without FLO selective pressure. Meanwhile, the abundances of floR under anaerobic condition were always lower than that under aerobic condition, suggesting that anaerobic biotreatment systems might be more suitable for the effective control of target ARGs. The higher abundance of floR in plasmid DNA than in genome also indicated that the potential transmission risk of mobile ARGs should not be ignored. In addition, the relative abundance of intI1 was positively correlated with floR in its corresponding genomic or plasmid DNA (p < 0.05), which also increased the potential horizontal transfer risk of target ARGs. This study provides new insights into the effect of preferential UV photolysis as a pretreatment method for the enhancement of metabolic performance and source control of target ARGs in subsequent biotreatment processes. KEY POINTS: • Sufficient UV photolytic pretreatment efficiently controlled the abundance of floR • A synchronous decrease in abundance of intI1 reduced the risk of horizontal transfer • An appreciable abundance of floR in plasmid DNA was a potential source of total ARGs.

Identification and florfenicol-treatment of pseudomonas putida infection in gilthead seabream (Sparus aurata) fed on tilapia-trash-feed.

The present study aimed to determine the major cause of the high mortality affecting farmed gilthead seabream (Sparus aurata) and controlling this disease condition. Fifteen diseased S. aurata were sampled from a private fish farm located at Eldeba Triangle, Damietta, fish showed external skin hemorrhages, and ulceration. Bacterial isolates retrieved from the diseased fish were identified biochemically as Pseudomonas putida and then confirmed by phylogenetic analysis of the 16 S rRNA gene sequence. P. putida was also isolated from three batches of tilapia-trash feed given to S. aurata. Biofilm and hemolytic assay indicated that all P. putida isolates produced biofilm, but 61.11% can haemolyse red blood cells. Based on the antibiotic susceptibility test results, P. putida was sensitive to florfenicol with minimum inhibitory concentrations ranging between 0.25 and 1.0 µg mL- 1, but all isolates were resistant to ampicillin and sulfamethoxazole-trimethoprim. Pathogenicity test revealed that P. putida isolate (recovered from the tilapia-trash feed) was virulent for S. aurata with LD50 equal to 4.67 × 107 colony forming unit (CFU) fish- 1. After intraperitoneal (IP) challenge, fish treated with 10 mg kg- 1 of florfenicol showed 16.7% mortality, while no mortality was recorded for the fish group that received 20 mg kg- 1. The non-treated fish group showed 46.7% mortality after bacterial challenge. HPLC analysis of serum florfenicol levels reached 1.07 and 2.52 µg mL- 1 at the 5th -day post-drug administration in the fish groups received 10 and 20 mg kg- 1, respectively. In conclusion, P. putida was responsible for the high mortality affecting cultured S. aurata, in-feed administration of florfenicol (20 mg kg- 1) effectively protected the challenged fish.

Effect of florfenicol on Piscirickettsia salmonis biofilm formed in materials used in salmonid nets, nylon and high-density polyethylene.

Piscirickettsiosis is the most prevalent bacterial disease affecting seawater salmon in Chilean salmon industry. Antibiotic therapy is the first alternative to counteract infections caused by Piscirickettsia salmonis. The presence of bacterial biofilms on materials commonly used in salmon farming may be critical for understanding the bacterial persistence in the environment. In the present study, the CDC Biofilm Reactor® was used to investigate the effect of sub- and over-MIC of florfenicol on both the pre-formed biofilm and the biofilm formation by P. salmonis under the antibiotic stimuli on Nylon and high-density polyethylene (HDPE) surfaces. This study demonstrated that FLO, at sub- and over-MIC doses, decreases biofilm-embedded live bacteria in the P. salmonis isolates evaluated. However, it was shown that in the P. salmonis Ps007 strain the presence of sub-MIC of FLO reduced its biofilm formation on HDPE surfaces; however, biofilm persists on Nylon surfaces. These results demonstrated that P. salmonis isolates behave differently against FLO and also, depending on the surface materials. Therefore, it remains a challenge to find an effective strategy to control the biofilm formation of P. salmonis, and certainly other marine pathogens that affect the sustainability of the Chilean salmon industry.

Mechanism of sturgeon intestinal inflammation induced by Yersinia ruckeri and the effect of florfenicol intervention.

The mechanism by which Y. ruckeri infection induces enteritis in Chinese sturgeon remains unclear, and the efficacy of drug prevention and control measures is not only poor but also plagued with numerous issues. We conducted transcriptomic and 16 S rRNA sequencing analyses to examine the differences in the intestinal tract of hybrid sturgeon before and after Y. ruckeri infection and florfenicol intervention. Our findings revealed that Y. ruckeri induced the expression of multiple inflammatory factors, including il1ß, il6, and various chemokines, as well as casp3, casp8, and multiple tumor necrosis factor family members, resulting in pathological injury to the body. Additionally, at the phylum level, the relative abundance of Firmicutes and Bacteroidota increased, while the abundance of Plesiomonas and Cetobacterium decreased at the genus level, altering the composition of the intestinal flora. Following florfenicol intervention, the expression of multiple apoptosis and inflammation-related genes was down-regulated, promoting tissue repair. However, the flora became further dysregulated, increasing the risk of infection. In conclusion, our analysis of the transcriptome and intestinal microbial composition demonstrated that Y. ruckeri induces intestinal pathological damage by triggering apoptosis and altering the composition of the intestinal microbiota. Florfenicol intervention can repair pathological damage, but it also exacerbates flora imbalance, leading to a higher risk of infection. These findings help elucidate the molecular mechanism of Y. ruckeri-induced enteritis in sturgeon and evaluate the therapeutic effect of drugs on intestinal inflammation in sturgeon.

Assessing the ecotoxicity of florfenicol exposure at environmental levels: A case study of histology, apoptosis and microbiota in hepatopancreas of Eriocheir sinensis.

The intensification of production practices in the aquaculture industry has led to the indiscriminate use of antibiotics to combat diseases and reduce costs, which has resulted in environmental pollution, posing serious threats to aquaculture sustainability and food safety. However, the toxic effect of florfenicol (FF) exposure on the hepatopancreas of crustaceans remains unclear. Herein, by employing Chinese mitten crab (Eriocheir sinensis) as subjects to investigate the toxic effects on histopathology, oxidative stress, apoptosis and microbiota of hepatopancreas under environment-relevant (0.5 and 5 µg/L), and extreme concentrations (50 µg/L) of FF. Our results revealed that the damage of hepatopancreas tissue structure caused by FF exposure in a dose-and time-dependent manner. Combined with the increased expression of apoptosis-related genes (Caspase 3, Caspase 8, p53, Bax and Bcl-2) at mRNA and protein levels, activation of catalase (CAT) and superoxide dismutase (SOD), and malondialdehyde (MDA) accumulation, FF exposure also induced oxidative stress, and apoptosis in hepatopancreas. Interestingly, 7 days exposure triggered more pronounced toxic effect in crabs than 14 days under environment-relevant FF concentration. Integrated biomarker response version 2 (IBRv2) index indicated that 14 days FF exposure under extreme concentration has serious toxicity effect on crabs. Furthermore, 14 days exposure to FF changed the diversity and composition of hepatopancreas microbiota leading remarkable increase of pathogenic microorganism Spirochaetes following exposure to 50 µg/L of FF. Taken together, our study explained potential mechanism of FF toxicity on hepatopancreas of crustaceans, and provided a reference for the concentration of FF to be used in culture of Chinese mitten crab.

Enhancement of dissolution rate and oral bioavailability of poorly soluble drug florfenicol by using solid dispersion and effervescent disintegration technology.

OBJECTIVE: Florfenicol(FF) is an excellent veterinary antibiotic, limited by poor solubility and poor bioavailability. SIGNIFICANCE: Here in, we aimed to explore the applicability of fast disintegrating tablets compressed from Florfenicol-loaded solid dispersions (FF-SD-FDTs) to improve the dissolution rate and oral bioavailability of Florfenicol. METHODS: Utilizing selecting appropriate preparation methods and carriers, the solid dispersions of Florfenicol (FF-SDs) were prepared by solvent evaporation and the fast disintegrating tablets (FF-SD-FDTs) were prepared by the direct compression (DC) method. RESULTS: The tablet properties including hardness, friability, disintegration time, weight variation, etc. all met the specifications of Chinese Veterinary Pharmacopeia(CVP). FF-SD-FDTs significantly improved drug dissolution and dispersion of FF in vitro compared to florfenicol conventional tablets (FF-CTs). A pharmacokinetics study in German shepherd dogs proved the AUC0-∞ and Cmax values of FF-SD-FDTs are 1.38 and 1.38 times more than FF-CTs, respectively. CONCLUSIONS: Overall, it can be concluded that FF-SD-FDTs with excellent disintegration and dissolution properties were successfully produced, which greatly improved the oral bioavailability of the poorly soluble drug FF, and the study provided a new idea for a broader role of FF in pet clinics.

Pharmacokinetic characteristics of florfenicol in green sea turtles (Chelonia mydas) and hawksbill sea turtles (Eretmochelys imbricata) after intramuscular administration.

The pharmacokinetics of florfenicol (FFC) in green sea and hawksbill sea turtles were evaluated following intramuscular (i.m.) administration at two different dosages of 20 or 30 mg/kg body weight (b.w.). This study (longitudinal design) used 5 green sea and 5 hawksbill sea turtles for the two dosages. Blood samples were collected at assigned times up to 168 h. FFC plasma samples were analyzed using validated high-performance liquid chromatography equipped with diode array detection. The pharmacokinetic analysis was performed using a non-compartment approach. The FFC plasma concentrations increased with the dosage. The elimination half-life was similar between the treatment groups (range 19-25 h), as well as the plasma protein binding (range 18.59%-20.65%). According to the surrogate PK/PD parameter (T > MIC, 2 µg/mL), the 20 and 30 mg/kg dosing rates should be effective doses for susceptible bacterial infections in green sea and hawksbill sea turtles.

Florfenicol urinary excretion and its potential for treating canine urinary tract infections.

The canine urinary excretion of florfenicol was evaluated to explore its potential for treating urinary tract infections. Nine healthy male intact purpose-bred Beagles and four healthy client-owned dogs each received a single oral dose of florfenicol 20 mg/kg (300 mg/mL parenteral solution) with food. All voluntary urinations were collected for 12 h. Although florfenicol is reportedly bitter tasting, 7/9 Beagles and 4/4 client-owned dogs completely ingested the florfenicol and were enrolled; salivation (n = 1) and headshaking (n = 3) were observed. The last measured urine florfenicol concentrations were variable: Beagles (0.23-3.19 mcg/mL), Pug (3.01 mcg/mL) English Setter (21.29 mcg/mL), Greyhound (32.68 mcg/mL), and Standard Poodle (13.00 mcg/mL). Urine half-life was similar for the Beagles and the Pug, 0.75-1.39 h, whereas the half-life was 1.70-1.82 h for the English Setter, Greyhound, and Standard Poodle. Larger breed dogs exceeded 8 mcg/mL florfenicol (wild-type cutoff) in their urine at 12 h, whereas the Beagles and Pug had <8 mcg/mL; it is unclear if this is an individual, breed, or size difference. These data suggest oral florfenicol may need to be administered q6-12h for canine urinary tract infections, but further data are needed (more enrolled dogs, multiple-dose regimens) before considering clinical trials or breed-specific differences.

Development of a QuEChERS-HPLC-FLD Procedure for the Simultaneous Detection of Residues of Florfenicol, Its Metabolite Florfenicol Amine, and Three Fluoroquinolones in Eggs.

A method utilizing high-performance liquid chromatography-fluorescence detection (HPLC-FLD) has been developed and refined for the simultaneous detection of florfenicol (FF) and its metabolite florfenicol amine (FFA) along with three fluoroquinolone (ciprofloxacin (CIP), enrofloxacin (ENR), and sarafloxacin (SAR)) residues in different parts of eggs (whole egg, egg yolk, and egg albumen). The QuEChERS ("Quick, easy, cheap, effective, rugged, and safe") procedure utilized 0.1 M disodium EDTA solution, water, and acetonitrile as extractants; sodium sulfate, sodium chloride, and trisodium citrate as dehydrating salts; and N-propylethylenediamine and C18 as adsorbents. A dual-channel FLD method was utilized to analyze the target compounds using an XBridge BEH C18 chromatographic column (4.6 mm × 150 mm, 5 µm). The mobile phase was employed isocratically using a solution of 0.01 M sodium dihydrogen phosphate, 0.005 M sodium dodecyl sulfate, and 0.1% triethylamine (pH 4.8) in combination with acetonitrile at a ratio of 65:35 (V/V). The limits of detection (LOD) and quantification (LOQ) of the analytes ranged from 0.03 to 1.5 µg/kg and from 0.1 to 5.0 µg/kg, respectively. The recoveries of the analytes in the blank egg samples ranged from 71.9% to 94.8% when reference standard concentrations of the LOQ, half of the maximum residual limit (MRL), MRL, and twice the MRL were added. The parameters of the presented protocol were validated and subsequently applied to the analysis of real samples, demonstrating the applicability and reliability of the method.

Effects of florfenicol on the antioxidant and immune systems of Chinese soft-shelled turtle (Pelodiscus sinensis).

Florfenicol is a commonly used antibiotic for the treatment of bacterial diseases of the Chinese soft-shelled turtle (Pelodiscus sinensis). The study investigated the effects of florfenicol on the antioxidant and immune system of P. sinensis. Results showed that the total antioxidant capacity (T-AOC), superoxide dismutase (SOD), and catalase (CAT) activities were significantly increased in the 10 mg/kg and 40 mg/kg florfenicol treatment groups compared with the control group. Besides, the malondialdehyde (MDA) content was significantly increased, and the glutathione peroxidase (GSH-Px) activity was significantly decreased with 40 mg/kg florfenicol treatment. In addition, florfenicol has effects on the immune system, 10 mg/kg of florfenicol significantly promoted the activities of acid phosphatase (ACP) and alkaline phosphatase (AKP), whereas 40 mg/kg of florfenicol significantly inhibited their activities. To elucidate the molecular mechanisms, a comparative transcriptome analysis was conducted. A total of 59 differentially expressed genes (DEGs) and 12 significantly enriched KEGG pathways were identified in the 10 mg/kg group; 150 DEGs and 10 significantly enriched KEGG pathways were identified in the 40 mg/kg group. Among them, the complement and coagulation cascade pathways were the most significant which may play an important regulatory role in the immune response. The MADCAM1, STAT3, and IL4I1 genes may be the key genes of florfenicol affecting the immune response. The APOA1, APOA4, SPLA2, FADS1, and FADS2 genes may play a key role in anti-inflammatory and antioxidant effects through redox-related pathways. The study lays the foundation for a deeper understanding of the mechanism of the florfenicol effect on P. sinensis.

Insights into Electrochemical Dehalogenation by Non-Noble Metal Single-Atom Cobalt with High Efficiency and Low Energy Consumption.

It is critical to discover a non-noble metal catalyst with high catalytic activity capable of replacing palladium in electrochemical reduction. In this work, a highly efficient single-atom Co-N/C catalyst was synthesized with metal-organic frameworks (MOFs) as a precursor for electrochemical dehalogenation. X-ray absorption spectroscopy (XAS) revealed that Co-N/C exhibited a Co-N4 configuration, which had more active sites and a faster charge-transfer rate and thus enabled the efficient removal of florfenicol (FLO) at a wide pH, achieving a rate constant 3.5 and 2.1 times that of N/C and commercial Pd/C, respectively. The defluorination and dechlorination efficiencies were 67.6 and 95.6%, respectively, with extremely low Co leaching (6 µg L-1), low energy consumption (22.7 kWh kg-1), and high turnover frequency (TOF) (0.0350 min-1), demonstrating excellent dehalogenation performance. Spiking experiments and density functional theory (DFT) verified that Co-N4 was the active site and had the lowest energy barrier for forming atomic hydrogen (H*) (ΔGH*). Capture experiments, electron paramagnetic resonance (EPR), electrochemical tests, and in situ Fourier transform infrared (FTIR) proved that H* and direct electron transfer were responsible for dehalogenation. Toxicity assessment indicated that FLO toxicity decreased significantly after dehalogenation. This work develops a non-noble metal catalyst with broad application prospects in electrocatalytic dehalogenation.

The disinhibition effect of iron-based particles on anaerobic digestion of florfenicol-containing cow manure: Performance and mechanism.

The overuse of antibiotics has caused problems such as environmental pollution, increased antibiotic resistance of pathogenic bacteria, and inhibition of engineered microbial processes such as anaerobic digestion (AD). At present, mitigating the inhibition of antibiotics on the process of microbial recycling of organic matter by using additives has always been a research hotspot. In this study, the effects of the addition of three iron-based particles including zero-valent iron (ZVI), Fe2O3 and Fe3O4 on the biogas yield during the AD of cow manure containing florfenicol (FLO) were studied. It was found that by alleviating the acid accumulation, the addition of low-concentration ZVI, Fe2O3 and high-concentration Fe3O4 enhanced the maximum methane production rate of FLO-containing cow manure during AD to 3.5, 1.7 and 3.6 times, respectively, while high concentration of ZVI will lead to the crash of the AD system due to the rise of pH. Within the concentration range of iron-based particles dosed in this study, the Fe3O4 dosage showed a significant positive correlation with the cumulative methane production enhancement rate (p < 0.01). The sum of the relative abundances of Limnobacter and Pseudomonas was correlated with the absolute abundance of floR gene with the Pearson correlation coefficient of 0.9457 (p < 0.01), indicating the possibility of these two genera being the potential host bacteria for floR gene.

In vitro assessment of PEG-6000 coated-ZnO nanoparticles: modulating action to the resisted antibiotic activity against APEC.

BACKGROUND: Avian pathogenic Escherichia coli (APEC) are considered a growing health problem to both poultry and the public, particularly due to its multi-drug resistance. Zinc oxide nanoparticles (ZnO-NPs) are a promising multi-benefit candidate. This study focused on boosting the antimicrobial effect of the chemically synthesized ZnO-NPs using Polyethylene glycol-6000 (PEG-6000) and evaluating their potential to recover the sensitivity of Florfenicol and Streptomycin-resistant APEC to these drugs in a concentration range of 0.1-0.4 mg/mL. Four samples of ZnO-NPs were formulated and tested microbiologically. RESULTS: The physicochemical characterization showed well-crystallized spherical in situ synthesized ZnO-NPs using PEG-6000 (surfactant) and ethanol (co-surfactant) of ∼19-67 nm particle size after coating with PEG-6000 molecules. These ZnO-NPs demonstrated a strong concentration-dependent antibacterial effect against multidrug-resistant APEC strains, with a minimum inhibitory concentration of 0.1 mg/mL, Combining PEG-6000 coated in situ synthesized ZnO-NPs and Florfenicol induced 60% high sensitivity (30 mm inhibitory-zone), 30% intermediate sensitivity, and 10% resistance against APEC strains. The combination with Streptomycin revealed 50% high sensitivity, 30% intermediate sensitivity, and 20% resistance with a 20 mm maximum zone of inhibition using agar well diffusion test. CONCLUSION: In situ preparation of ZnO-NPs using PEG-6000 and ethanol followed by coating with PEG-6000 enhanced its antibacterial activity in minimum inhibitory concentration and regained the efficacy of Florfenicol and Streptomycin against APEC, referring to a non-antibiotic antimicrobial alternative and an effective combination regimen against multidrug-resistant APEC E. coli in veterinary medicine.

Florfenicol sustained-release granules: an in vitro-in vivo correlation study in pigs.

The objective of this study was to synthesize and characterize pharmaceutical characteristics of florfenicol sustained-release granules (FSRGs) in vitro and in vivo. FSRGs were synthesized using monostearate, polyethylene glycol 4000 and starch. In vitro dissolution profiles were studied using the rotating basket method in pH 1.2 HCl solution and pH 4.3 acetate buffer. Twenty-four male healthy Landrace×Yorkshire pigs were equally divided into three groups and administered a 20 mg/kg i.v bolus of florfenicol solution and dosed orally with FSRGs in the fasting and fed states. The Higuchi model was the best fit for the drug release profile in pH 1.2 and pH 4.3 media, and the mechanism of drug dissolution was governed by both diffusion and dissolution. We established a level A in vitro - in vivo correlation for FSRGs and the in vivo profile of the FSRGs can be estimated by the in vitro drug release.

Impact of tectoridin on the pharmacokinetics of florfenicol via targeting cytochrome P450 and P-glycoprotein of rats.

Belamcanda chinensis (L.) DC, commonly used with florfenicol in Chinese veterinary clinics for respiratory tract infections, contains the major effective isoflavone, tectoridin (TEC). This study aimed to investigate the impact of TEC co-administration on the pharmacokinetics of florfenicol in vivo.Male rats received oral TEC (50 mg/kg BW) or sterile water for seven days, followed by a single oral dose of florfenicol (25 mg/kg BW) on the 8th day. Non-compartmental methods analysed the pharmacokinetics of florfenicol, while real-time reverse transcription polymerase chain reaction (RT-PCR), Western blot, and immunohistochemical analyses measured expression levels of cytochrome P450 (CYP) isoforms in the liver and P-glycoprotein (P-gp) in the jejunum.TEC significantly decreased florfenicol's AUC(0-∞), MRT(0-∞), t1/2z, Vz/F, and Cmax by 24.75%, 18.43%, 55.47%, 43.05%, and 19.48%, while increasing CLz/F by 33.33%. TEC also up-regulated hepatic CYP1A2 and CYP3A1 mRNA expression, as well as intestinal MDR1, by 1.39-fold, 1.85-fold, and 1.65-fold. This coincided with a respective increase in protein expression by 1.37-fold, 1.39-fold, and 1.43-fold.These findings suggest that TEC-induced alterations in the pharmacokinetics of florfenicol may be attributed to increased CYP and P-gp expression. Further investigations are warranted to understand the implications of these findings on the clinical effectiveness of florfenicol in veterinary practice.

Coptisine modulates the pharmacokinetics of florfenicol by targeting CYP1A2, CYP2C11 and CYP3A1 in the liver and P-gp in the jejunum of rats: a pilot study.

Coptisine (COP) is the main active ingredient of Coptis chinensis. In Chinese veterinary clinics, Coptis chinensis is commonly used alongside florfenicol to treat intestinal infections. The goal of this study was to investigate the impact of COP co-administration on the pharmacokinetics of florfenicol in rats.Male Sprague-Dawley rats were orally administered COP (50 mg/kg BW) or sterile water for 7 consecutive days, followed by a single oral dose of florfenicol (25 mg/kg BW) on the 8th day. Pharmacokinetics of florfenicol were analysed using non-compartmental methods, while expression levels of cytochrome P450 (CYP) isoforms in the liver and P-glycoprotein (P-gp) in the jejunum were measured using real-time RT-PCR, Western blot and immunohistochemical analyses.Co-administration of COP and florfenicol significantly increased AUC(0-∞), MRT(0-∞), and Cmax of florfenicol, while CLz/F was significantly decreased. COP down-regulated the expression of CYP1A2, CYP2C11, and CYP3A1 in the liver, as well as P-gp in the jejunum.These findings suggest that co-administration of COP with florfenicol alters the pharmacokinetics of florfenicol in rats. The down-regulation of CYP and P-gp expression may contribute to this effect. Therefore, the co-administration of COP with florfenicol may enhance the prophylactic or therapeutic efficacy of florfenicol in veterinary practice.