Efficient treatment of veterinary pharmaceutical industrial wastewater by catalytic ozonation process: degradation of enrofloxacin via molecular ozone reactions.

The study focused on the efficacious performance of bimetallic Fe-Zn loaded 3A zeolite in catalytic ozonation for the degradation of highly toxic veterinary antibiotic enrofloxacin in wastewater of the pharmaceutical industry. Batch experiments were conducted in a glass reactor containing a submerged pump holding catalyst pellets at suction. The submerged pump provided the agitation and recirculation across the solution for effective contact with the catalyst. The effect of ozone flow (0.8-1.55 mg/min) and catalyst dose (5-15 g/L) on the enrofloxacin degradation and removal of other conventional pollutants COD, BOD5, turbidity was studied. In batch experiments, 10 g of Fe-Zn 3A zeolite efficiently removed 92% of enrofloxacin, 77% of COD, 69% BOD5, and 61% turbidity in 1 L sample of pharmaceutical wastewater in 30 min at 1.1 mg/min of O3 flow. The catalytic performance of Fe-Zn 3A zeolite notably exceeded the removal efficiencies of 52%, 51%, 52%, and 59% for enrofloxacin, COD, BOD5, and turbidity, respectively, achieved with single ozonation process. Furthermore, an increase in the biodegradability of treated pharmaceutical industrial wastewater was observed and made biodegradable easily for subsequent treatment.

Intramuscular therapeutic doses of enrofloxacin affect microbial community structure but not the relative abundance of fluoroquinolones resistance genes in swine manure.

Livestock manure is a major source of veterinary antibiotics and antibiotic resistance genes (ARGs). Elucidation of the residual characteristics of ARGs in livestock manure following the administration of veterinary antibiotics is critical to assess their ecotoxicological effects and environmental contamination risks. Here, we investigated the effects of enrofloxacin (ENR), a fluoroquinolone antibiotic commonly used as a therapeutic drug in animal husbandry, on the characteristics of ARGs, mobile genetic elements, and microbial community structure in swine manure following its intramuscular administration for 3 days and a withdrawal period of 10 days. The results revealed the highest concentrations of ENR and ciprofloxacin (CIP) in swine manure at the end of the administration period, ENR concentrations in swine manure in groups L and H were 88.67 ± 45.46 and 219.75 ± 88.05 mg/kg DM, respectively. Approximately 15 fluoroquinolone resistance genes (FRGs) and 48 fluoroquinolone-related multidrug resistance genes (F-MRGs) were detected in swine manure; the relative abundance of the F-MRGs was considerably higher than that of the FRGs. On day 3, the relative abundance of qacA was significantly higher in group H than in group CK, and no significant differences in the relative abundance of other FRGs, F-MRGs, or MGEs were observed between the three groups on day 3 and day 13. The microbial community structure in swine manure was significantly altered on day 3, and the altered community structure was restored on day 13. The FRGs and F-MRGs with the highest relative abundance were qacA and adeF, respectively, and Clostridium and Lactobacillus were the dominant bacterial genera carrying these genes in swine manure. In summary, a single treatment of intramuscular ENR transiently increased antibiotic concentrations and altered the microbial community structure in swine manure; however, this treatment did not significantly affect the abundance of FRGs and F-MRGs.

Therapeutic efficacy of enrofloxacin in treatment of Francisella orientalis infections in juvenile Nile tilapia (Oreochromis niloticus L.).

Outbreaks of infections by Francisella orientalis represent one of the main obstacles to Nile tilapia (Oreochromis niloticus L.) farming. It is responsible for acute mortality in fingerlings and juveniles. The main control measure available is oral antibiotic therapy. This study compared the therapeutic efficacy of the antibiotics enrofloxacin and oxytetracycline, the most commonly used antimicrobial, against francisellosis in juvenile Nile tilapia (O. niloticus). Fish were challenged with a virulent isolate of F. orientalis and treated with medicated feed containing one of two doses of oxytetracycline (100 or 300 mg/kg of live weight (LW)) or 10 mg/kg of LW of enrofloxacin. The positive and negative control groups received feed without antibiotics; the negative control group was unchallenged. The results showed that enrofloxacin at a dose of 10 mg/kg of LW is effective against francisellosis in juvenile Nile tilapia (O. niloticus). Treatment with oxytetracycline did not eliminate the pathogen from the infected host, and the surviving fish became carriers. Enrofloxacin was able to cure the fish of infection with F. orientalis. This study suggests that enrofloxacin is a better option for treating francisellosis in Nile tilapia (O. niloticus L.). It controls mortality and avoids the carrier state in the fish, thus reducing the possibility of recurrence in the affected batches.

Characterization and removal mechanism of a novel enrofloxacin-degrading microorganism, Microbacterium proteolyticum GJEE142 capable of simultaneous removal of enrofloxacin, nitrogen and phosphorus.

In the study, a novel ENR-degrading microorganism, Microbacterium proteolyticum GJEE142 was isolated from aquaculture wastewater for the first time. The ENR removal of strain GJEE142 was reliant upon the provision of limited additional carbon source, and was adaptative to low temperature (13 â„ƒ) and high salinity (50‰). The ENR removal process, to which intracellular enzymes made more contributions, was implemented in three proposed pathways. During the removal process, oxidative stress response of strain GJEE142 was activated and the bacterial toxicity of ENR was decreased. Strain GJEE142 could also achieve the synchronous removal of ammonium, nitrite, nitrate and phosphorus with the nitrogen removal pathways of nitrate → nitrite → ammonium → glutamine → glutamate → glutamate metabolism and nitrate → nitrite → gaseous nitrogen. The phosphorus removal was implemented under complete aerobic conditions with the assistance of polyphosphate kinase and exopolyphosphatase. Genomic analysis provided corresponding genetic insights for deciphering removal mechanisms of ENR, nitrogen and phosphorus. ENR, nitrogen and phosphorus in both actual aquaculture wastewater and domestic wastewater could be desirably removed. Desirable adaptation, excellent performance and wide distribution will make strain GJEE142 the hopeful strain in wastewater treatment.

A novel continuous all-weather photo-electric synergistic treatment system for refractory organic compounds and its application in degrading enrofloxacin.

A novel continuous all-weather photo-electric synergistic treatment system was proposed in this study for refractory organic compounds, which overcame the defects of conventional photo-catalytic treatments that rely on light irradiation and thus cannot achieve all-weather continuous treatment. The system used a new photocatalyst (MoS2/WO3/carbon felt) with the characteristics of easy recovery and fast charge transfer. The system was systematically tested in degrading enrofloxacin (EFA) under real environmental conditions in terms of treatment performance, pathways and mechanisms. The results showed that the EFA removal of photo-electric synergy substantially increased by 1.28 and 6.78 times, compared to photocatalysis and electrooxidation, respectively, with an average removal of 50.9% under the treatment load of 832.48 mg m-2 d-1. Possible treatment pathways of EFA and mechanism of the system were found to be mainly the loss of piperazine groups, the cleavage of the quinolone portion and the promotion of electron transfer by bias voltage.

Use of Enrofloxacin and Hydrotherapy in the Management of Fibrodysplasia Ossificans Progressiva (FOP) in a Savannah Cat.

FOP is a rare genetic condition, described mainly in man and cats, characterized by progressive, painful debilitation and shortened lifespan. A 10-month-old neutered male Savannah cat was referred for progressive gait abnormalities and multifocal firm masses within the soft-tissues that were unresponsive to previous treatment. Diagnosis of FOP was based on histopathological evaluation of intralesional biopsies, which revealed osteo-cartilaginous metaplasia and fibrocellular proliferation with intralesional chondrogenesis and endochondral ossification. The cat was managed with 5 mg/kg BID enrofloxacin and hydrotherapy for 3 years until acute death. During that three-year period, the cat displayed consistent improvement in endurance, quality of life, and range of motion. Postmortem histopathology further confirmed the diagnosis of FOP via identification of intramuscular and intra-fascial ossification with lymphoplasmacytic infiltration, degeneration, and regeneration of adjacent myocytes. To the authors' knowledge, this is the first report of long-term enrofloxacin treatment and hydrotherapy for the management of FOP in a cat, leading to improved mobility and survival time, and the first report of FOP in an exotic breed cat.

Effect of external carbon addition and enrofloxacin on the denitrification and microbial community of sequencing batch membrane reactor treating synthetic mariculture wastewater.

The effect of sequencing batch membrane bioreactor (SMBR) on external carbon addition and enrofloxacin was investigated to treat synthetic mariculture wastewater. Anoxic/anaerobic and low COD/TN can improve the ammonia oxidation of the system, and the NH4+-N removal efficiency above 99%. External carbon was added and an anoxic environment was set to provide a suitable environment for denitrifying bacteria. When the external carbon source was 50-207 mg/L, the TN removal efficiency (31.82%-37.73%) and the COD of the effluent (28.85-36.58 mg/L) had little change. The partition resistance model showed that cake deposition resistance (RC,irr) and irreversible resistance (RPB) were the main components. And with the increase in cleaning times, the fouling rate of membrane components accelerated. Enrofloxacin can promote the TN removal efficiency (45.66%-93.74%) and had a significant effect on TM7a, Cohaesibacter, Vibrio and Phaeobacter.

Combined toxic effects of enrofloxacin and microplastics on submerged plants and epiphytic biofilms in high nitrogen and phosphorus waters.

With the wide application of plastic products, microplastic pollution has become a major environmental issue of global concern. Microplastics in aquatic environments can interact with organic pollutants, causing a combined effect on submerged macrophytes. This study investigated the response mechanisms of the submerged plant Myriophyllum verticillatum and epiphytic biofilm to the antibiotic enrofloxacin, microplastics, and their combined exposure in a high nitrogen and phosphorus environment. The results indicated that Myriophyllum verticillatum was not sensitive to enrofloxacin of 1 mg L-1, while 10 and 50 mg L-1 enrofloxacin inhibited the uptake of nitrogen and phosphorus by the plants, as well as triggered oxidative stress in the plant leaves, causing irreversible damage to the plant cells. In addition, enrofloxacin altered the structure of the leaf epiphytic biofilm community. Interestingly, 1, 5, and 20 mg L-1 microplastics had no significant effect on the plant, while they facilitated the aggregation of microorganisms, increasing the abundance of the leaf epiphyte biofilm. The combination of enrofloxacin and microplastics induced a synergistic effect on Myriophyllum verticillatum. Specifically, the rate of nitrogen and phosphorus uptake by the plant was reduced, the content of photosynthetic pigments decreased, and antioxidant enzyme activity was further increased. In addition, the diversity of the leaf epiphytic biofilm community was similar to the single enrofloxacin exposure. These results demonstrated the differences between single and combined exposures and provided a new theoretical basis to evaluate the harmful effects of enrofloxacin and microplastics on submerged macrophytes.

Targeting therapy effects of composite hyaluronic acid/chitosan nanosystems containing inclusion complexes.

In order to solve the difficulties in the treatment of Staphylococcus aureus infections, a novel enrofloxacin-cyclodextrin (ß-CD) inclusion complexes (IC) containing hyaluronic acid/chitosan (HA/CS) self-assemble composite nanosystems covered by poloxamer 188 was designed in our previous study. In this study, the sustained release peforemance, targeting delivery, and therapy effects of the enrofloxacin-composite nanosystems were evaluated in vivo. The enrofloxacin-composite nanosystems had uniform size and smooth surface with drug loading capacity (LC) of 9.92 ± 0.3%. Thermogravimetric analysis (TGA) showed that the material used for the preparation of the enrofloxacin-composite nanosystems did not affect the thermal stability of enrofloxacin. Compared with enrofloxacin injection and enrofloxacin polymeric nanoparticles, the enrofloxacin-composite nanosystems had excellent sustained-release performance in vivo. The enrofloxacin-composite nanosystems have specific targeting to the infection site of Staphylococcus aureus. The excellent sustained release and targeting delivery properties ensure that the anti-infective treatment effect of the enrofloxacin-composite nanosystems in vivo was higher than that of enrofloxacin injection and enrofloxacin polymeric nanoparticles. It can more effectively promote the wound healing. These results suggest that our previous designed enrofloxacin-composite nanosystems will be a promising formulation for effective targeting therapy of Staphylococcus aureus infections.

Metabolites in Milk after Enrofloxacin Treatment and Their Persistence to Temperature.

In this work, metabolomic profile changes in milk from cows affected by mastitis and treated with enrofloxacin (ENR) have been studied using LC-HRMS techniques. Principal component analysis was applied to the obtained results, and the interest was focused on changes affecting compounds without a structural relationship to ENR. Most of the compounds, whose concentrations were modified as a result of the pharmacological treatment and/or the pathological status, were related to amino acids and peptides. Compounds that may become possible biomarkers for either disease or treatment have been detected. Additionally, the alterations caused by thermal processes, such as those applied to milk before consumption, on the identified metabolites have also been considered.

Sulfidised nanoscale zerovalent iron-modified pitaya peel-derived carbon for enrofloxacin degradation and swine wastewater treatment: Combination of electro-Fenton and bio-electro-Fenton process.

In this study, a new Fenton system combining electro-Fenton and bio-electro-Fenton (EF-BEF) processes was proposed for ENR degradation and swine wastewater treatment, and pitaya peel-derived carbon modified with sulfidised nanoscale zerovalent iron (SnZVI) was developed as a catalyst for the system. The as-prepared PPC-800 carbon displayed a hierarchical porous structure (693.5 m2/g), abundant oxygen-containing groups, and carbon defects, which endowed it with a good adsorption capacity, high H2O2 generation capacity (151.9 ± 10.5 mg/L) during the EF period, and good power production performance (194.3 ± 12.50 mW/m2) during the BEF period. When modified with SnZVI, despite the decrease in the adsorption capacity and power output (102.05 ± 4.05 mW/m2), the SnZVI@PPC-2 exhibited the best ENR removal performance with that of 98.9 ± 0.2% in the EF period and 86.2 ± 5.6% during the BEF period. An increase in the current intensity and air flow rate promoted ENR degradation. Finally, swine wastewater was treated using the SnZVI@PPC-2 EF-BEF system, and 97.9 ± 1.3% of the TOC was removed using the combined system.

One-step synthesis of garlic peel derived biochar by concentrated sulfuric acid: Enhanced adsorption capacities for Enrofloxacin and interfacial interaction mechanisms.

This study put forward a one-step carbonization method by concentrated sulfuric acid to prepare garlic peel derived biochar, and the synthetic conditions were optimized by L16(45) orthogonal experiments. Notably, in order to study the differences between the proposed synthetic method and the conventional pyrolysis method, the concentrated sulfuric acid carbonized garlic peels biochar (CSGPB) was compared with pyrolysis derived garlic peel biochar (HTGPB) in characterization and adsorption capacities for Enrofloxacin (ENR). Results showed that CSGPB exhibited more graphite-like structures with more active functional groups on the surface, and the equilibrium adsorption capacity of CSGPB (142.3 mg g-1) was 13.7 times of HTGPB (10.4 mg g-1) under identical conditions. Moreover, the adsorption behaviors including adsorption kinetics, isotherms and thermodynamics of CSGPB for ENR were fully investigated and discussed. Based on the above experiments, density functional theory (DFT) simulations were performed to reveal the interfacial interaction and adsorption mechanism. Results showed π-π interaction between quinolone moieties of ENR and graphite-like structures in CSGPB might be the dominant mechanism. As for the functional groups, the adsorption energies were -40.46, -15.21 and -5.96 kJ mol-1 for -SO3H, -OH and -COOH, respectively, which indicated -SO3H was the most active functional groups on the surface of CSGPB. This study provided a new sustainable perspective for the design of efficient biochars, and explored the interfacial interaction mechanism of antibiotics removal on biochars.

Removal of sulfonamide and enrofloxacin from water by periphyton under different nitrogen and phosphorus concentrations.

Periphyton is an emerging biological technology for water purification. However, the removal effect of periphyton on antibiotic contaminants in water under different nitrogen and phosphorus levels remains largely unknown. In this study, four nitrogen and phosphorus levels [N-P (mg·L-1): 2-0.2, 5-0.5, 8-0.8, 11-1.1] were set up to grow periphyton outdoors in plastic crates. The growth, photosynthe-tic activity, species composition, and removal of sulfonamide and enrofloxacin were simulated at a medium scale. The results showed that biomass of the surrounding organisms increased with the increases of culture time. In contrast, the photosynthetic pigment content and photosynthetic activity showed a "single peak" pattern, which first decreased and then increased, indicating that algae in the biofilm would be stressed by antibioics but could quickly adapt and recover vitality. In addition, different nitrogen and phosphorus concentrations resulted in differences in community composition. With the increases of nutrient concentrations, species richness of periphyton algae gradually decreased. The relative abundance of Dictyosphaerium and Chlorella in each treatment was relatively high. Results of 16S rRNA high-throughput sequencing showed that the flora of Rhizobiaceae, Frankiales, and Moraxellaceae was significantly enriched in groups 2-0.2. The relative abundance of Chitinophagaceae in all the four treatments was the highest. The removal rate of sulfonamide in all treatments was higher than 50%, while the removal rate of enrofloxacin in all treatments was more than 90%. The removal rate of sulfonamide in (N-P) 2-0.2 mg·L-1 group (65.8%) was significantly higher than that in other groups, but with no significant difference in the removal rate of enrofloxacin among all treatments. The results showed that periphyton had an excellent ability to remove sulfonamide and enrofloxacin in a wide range of N-P levels. The removal rate of soluble nitrogen in water was not different in each treatment group, and the removal effect of soluble phosphorus was substantial. Our results provided primary data for the ecological removal of sulfonamide and enrofloxacin in water, which gave a new idea for the development of environmental removal technology for new antibiotic pollutants in water.

Effects of Selenium Conjugated to Insect Protein on Pharmacokinetics of Florfenicol and Enrofloxacin in Laying Hens.

In the context of increasing awareness on the dietary supplementation of organic selenium in commercial poultry production and ensuring safe egg production, the present study investigated the effects of selenium on the pharmacokinetics of the therapeutic use of florfenicol and enrofloxacin from perspectives of laying performance, selenium deposition in eggs, and drug residue in plasma, organs, and eggs. A 2 × 3 factorial arrangement with two kinds of drugs (florfenicol vs. enrofloxacin, 200 mg/kg) and three levels of dietary organic selenium SCIP (selenium conjugated to insect protein) (0, 2, and 5 mg/kg) was designed together with a blank control group. Healthy Hy-Line Brown laying hens (n = 252, 40-week-old and 90.0 ± 1.7% of egg production rate) were randomly allocated into one of seven treatments with six replicates and six hens per replicate. The experiment lasted for 42 days and consisted of three periods (adjusted stage, depositional stage, and eliminating stage) of 14 days each. These stages entail feeding of the laying hens with basal diets, addition of drugs and selenium synchronously into the diets, drug withdrawal from diet, and supply of selenium uninterruptedly in the diet. Egg production and feed intake were recorded on daily and weekly bases, respectively. The selenium content in egg yolk, egg white, and whole eggs and the drug residues in eggs, plasma, liver, kidney, and breast muscle were determined on days 2, 3, 5, 6, 7, 9, 11, and 14 of the depositional and eliminating stages. There was no significant difference (p > 0.05) in egg production among the dietary treatments, but feed intake decreased significantly (p < 0.05) in the drug treatment group compared to other groups. Dietary organic selenium decreased the residue of drugs in tissues and eggs, while the metabolism and deposition of selenium in laying hens were suppressed due to drug effects. The results of the present study are of significance to enrich the knowledge of the pharmacokinetics of florfenicol and enrofloxacin in laying hens and ensure the quality of poultry products.

Pharmacokinetics and pharmacodynamics of enrofloxacin treatment of Escherichia coli in a murine thigh infection modeling.

BACKGROUND: Enrofloxacin is an antibacterial drug with broad-spectrum activity that is widely indicated for veterinary use. We aim to develop the clinical applications of Enrofloxacin against colibacillosis by using the neutropenic mice thigh infection model. RESULTS: The minimum inhibitory concentration (MIC) distribution of 67 isolated E. coli strains to ENR was calculated using CLSI guidelines. Whereas, the MIC50 value calculation was considered as the population PD parameter for ENR against E. coli strains. The MIC values of 15 E. coli strains were found to be nearest to the MIC50 i.e., 0.25 µg/mL. Of all the tested strains, the PK-PD and E. coli disease model was established via selected E. coli strain i.e., Heilong 15. We analyzed the PK characteristics of ENR and its metabolite ciprofloxacin (CIP) following a single subcutaneous (s.c.) injection of ENR (1.25, 2.5, 5, 10 mg/kg). The concentration-time profiling of ENR within the plasma specimens was determined by considering the non-compartmental analysis (NCA). The basic PK parameters of ENR for the peak drug concentration (Cmax) and the area under the concentration-time curve (AUC) values were found to be in the range of 0.27-1.97 µg/mL and 0.62-3.14 µg.h/mL, respectively. Multiple s.c. injection over 24 h (1.25, 2.5, 5, 10 mg/kg at various time points i.e., 6, 8, 12, and 24 h respectively) were administered to assess the targeted PD values. The Akaike Information Criterion (AIC) was used to choose PD models, and the model with the lowest AIC was chosen. The inhibitory Emax model was employed to calculate the related PK-PD parameters. The results of our study indicated that there was a strong correlation between the AUC/MIC and various antibacterial activities (R2 = 0.9928). The target values of dividing AUC/MIC by 24 h for bacteriostatic action were 1-log10 reduction, 2-log10 reduction, and 3-log10 reduction 0.325, 0.4375, 0.63, and 0.95 accordingly. CONCLUSION: The identified pharmacodynamics targets for various antibacterial effects will be crucial in enhancing ENR clinical applications and serving as a key step in reducing bacterial resistance.

Phytobiotics blend as a dietary supplement for Nile tilapia health improvement.

Functional additives of natural origin included as dietary supplements have become an alternative to synthetic antibiotics to improve health and resistance to ecologically correct pathogenic diseases in fish farming. We tested whether incorporating a mixture of phytobiotics such as volatile oils of thyme, red thyme and pepper rosemary into the diet improves growth performance, oxidative stress, immune and hematological responses and resistance of juvenile Nile tilapia when subjected to a challenge with Aeromonas hydrophila compared to a synthetic antibiotic (enrofloxacin). The experimental design was completely randomized with three experimental groups: control diet, diets containing a mixture of thyme phytobiotic essential oils, red thyme and pepper rosemary (FTB) and the synthetic antibiotic enrofloxacin (ATB), with four replicates (14 fish per repetition/experimental unit). Plasma glucose levels, leukocyte respiratory activity, serum lysozyme levels, number of circulating erythrocytes and leukocytes, levels of lipid peroxidation (LPO), catalase (CAT) and glutathione S-transferase (GST) activity at the end of 20 days of feeding (phase) were evaluated and 24 h after exposure to bacteria (phase II). The supplementation of FTB and ATB did not change the performance parameters, but it was sufficient to increase lysozyme, leukocytes, neutrophils and monocytes after the bacterial challenge, reduction of CAT and LPO activity and the highest GST activity (P < 0.05). The results of the present study suggest that FTB as a dietary supplement has benefits and can replace synthetic ATB, including supplementation with FTB for 20 days to provide greater antioxidant protection in Nile tilapia, mitigate the impacts of stressors and modulate immunity, providing to fish greater resistance and protection against diseases.

Evaluation of the efficacy of enrofloxacin in rainbow trout (Oncorhynchus mykiss) following experimental challenge with Yersinia ruckeri.

BACKGROUND: Use of enrofloxacin in trout farms is reported, especially for the treatment of yersiniosis, albeit various dosing regimens have been used. Therefore, optimal doses should be investigated. METHODS: Five groups of 15 fish were challenged with Y. ruckeri. Two days later, three groups received feed containing enrofloxacin (ENR) at 1, 2.5 and 5 mg/kg fish respectively, during 7 days; one group received a single intraperitoneal injection of ENR at 10 mg/kg; and one group was left untreated. On day 15, surviving fish were euthanized. RESULTS: All fish survived in the group treated by injection, compared to 53%, 60% and 40% of the fish treated with 1, 2.5 and 5 mg/kg oral ENR, respectively, and 53% in the infected untreated group. CONCLUSION: A single intraperitoneal injection of ENR at 10 mg/kg seems more relevant than repeated oral administrations. The ENR oral doses used in trout farms should be revised.

Perinatal treatment of parents with the broad-spectrum antibiotic enrofloxacin aggravates contact sensitivity in adult offspring mice.

BACKGROUND: Antibiotics, while eliminating pathogens, also partially deplete commensal bacteria. Antibiotic-induced dysbiosis may contribute to the observed rise in "immune-mediated" diseases, including autoimmunity and allergy. The aim of this study is to investigate the impact of perinatal antibiotic treatment on T cell-mediated immune response in adult mice. METHODS: Oral treatment with broad-spectrum antibiotic enrofloxacin during gestation and breastfeeding or breastfeeding or gestation alone was used to evaluate whether antibiotic exposure early in life could modulate contact sensitivity (CS) in adult mice. RESULTS: Here, we demonstrated that enrofloxacin treatment during gestation and breastfeeding, but not during pregnancy or breastfeeding alone, aggravated CS reaction in adult mice measured by ear swelling. These data correlate with increased myeloperoxidase (MPO) activity in the ear extracts and elevated production of IL-6 and IL-17A by auricular lymph node cells (ELNC) and was not influenced by food consumption and body weight. In each dosing regimen, enrofloxacin treatment reduced the relative abundance of Enterococcus spp. but did not influence the relative abundances of Lactobacillus, Clostridium cluster XIVa, XIVab, I, Bacteroidetes, and segmented filamentous bacteria (SFB). However, prolonged enrofloxacin-treatment during both gestation and breastfeeding decreased the relative abundance of Clostridium cluster IV. CONCLUSION: These data show that long-term perinatal enrofloxacin treatment induces intestinal dysbiosis, characterized by decreased levels of anti-inflammatory Clostridium cluster IV, and alters T cell-dependent immune responses, enhancing CS reaction in adult mice.

Bacterial Causes for Mortality Syndrome in Some Marine Fish Farms with Treatment Trials.

BACKGROUND AND OBJECTIVE: Bacterial fish diseases constitute a major problem in aquaculture, it was found in the environment and under stressors cause severe economic losses to fish. This work aimed to investigate the bacterial causes and suitable treatments of mass mortality in some cultured marine fish farms in Damietta governorate. MATERIALS AND METHODS: The study was performed on 5 farms suffered from mass mortality. Total of 100 diseased fish (10 sea bass and 10 sea bream/farm) and 20 water samples were randomly collected from these farms. Bacteriological examinations were carried out followed by in vitro sensitivity tests. Treatment trial was performed using the most effective antibacterial agent on isolated bacteria. RESULTS: From fish and water samples Pseudomonas spp., Aeromonas spp. and Vibrio spp. were isolated with the rat of (16, 10%), (22, 10%) and (28, 10%) respectively. These results were confirmed biochemically. Some virulence genes of isolated bacteria were detected using PCR; meanwhile, enrofloxacin reduced significantly the mortality rates in examined farms. CONCLUSION: It could be concluded that, Pseudomonas spp., Aeromonas spp. and Vibrio spp. are the main bacterial species causing mass mortality in marine fish farms. These bacteria were highly sensitive to enrofloxacin in vitro and in vivo.

The impact of therapeutic-dose induced intestinal enrofloxacin concentrations in healthy pigs on fecal Escherichia coli populations.

BACKGROUND: Knowledge of therapy-induced intestinal tract concentrations of antimicrobials allows for interpretation and prediction of antimicrobial resistance selection within the intestinal microbiota. This study describes the impact of three different doses of enrofloxacin (ENR) and two different administration routes on the intestinal concentration of ENR and on the fecal Escherichia coli populations in pigs. Enrofloxacin was administered on three consecutive days to four different treatment groups. The groups either received an oral bolus administration of ENR (conventional or half dose) or an intramuscular administration (conventional or double dose). RESULTS: Quantitative analysis of fecal samples showed high ENR concentrations in all groups, ranging from 5.114 ± 1.272 µg/g up to 39.54 ± 10.43 µg/g at the end of the treatment period. In addition, analysis of the luminal intestinal content revealed an increase of ENR concentration from the proximal to the distal intestinal tract segments, with no significant effect of administration route. Fecal samples were also screened for resistance in E. coli isolates against ENR. Wild-type (MIC≤0.125 µg/mL) and non-wild-type (0.125 < MIC≤2 µg/mL) E. coli isolates were found at time 0 h. At the end of treatment (3 days) only non-wild-type isolates (MIC≥32 µg/mL) were found. CONCLUSIONS: In conclusion, the observed intestinal ENR concentrations in all groups showed to be both theoretically (based on pharmacokinetic and pharmacodynamic principles) and effectively (in vivo measurement) capable of significantly reducing the intestinal E. coli wild-type population.