Productive and reproductive performance of crossbred dairy heifers with induced lactation and efficacy of antimicrobial therapy associated with internal teat sealants / Desempenho produtivo e reprodutivo de novilhas com lactação induzida e eficácia da terapia antimicrobiana associada com selante interno de tetos

This study evaluated (a) the efficacy of an association between injectable antibiotic therapy and sealant (ATBS) on milk yield (MY), somatic cell count (SCC), and prevalence of intramammary infections (IMI); and (b) the efficacy of gonadotropin-releasing hormone (GnRH) on follicular cyst (FCs) resolution (cyclicity at the 45th day in milk; DIM) and cumulative pregnancy rate (CPR) in heifers submitted to a lactation induction protocol (LIP). A total of 114 crossbred (Holstein × Jersey) heifers, with 34.7 ± 4.8 months and 439 ± 56.35 kg were submitted to LIP. On the 5th day of the LIP, the heifers were assigned to (i) ATBS (n = 57) with 7 mg/kg of norfloxacin associated with sealant and (ii) Control 1 (n = 57; CONT1) with no treatments. Lactation began on the 21st day of LIP and the 15th DIM, FCs were diagnosed and 106 heifers were randomized into two treatment groups with 53 heifers each: (i) GnRH (5 mL injectable GnRH) and (ii) Control 2 (CONT2; no treatment). Of the 114 heifers initially induced, 83.33% (n = 95) responded to LIP with an average MY of 15.19 kg/milk/day during 22 weeks of lactation. In the first 14 DIM, the IMI prevalence was 18% and 28% for heifers ATBS and CONT1 treated, respectively. Additionally, coagulase-negative Staphylococcus was the most frequently isolated group of pathogens. Mammary quarters that received ATBS treatment had a lower risk of IMI and SCC than CONT1. The cyclicity at 45 DIM was 68% (ATBS) and 35% (CONT1), and 57% and 46% for animals in the GnRH and CONT2. CPR was 60% in the ATBS group and 89% in CONT1, but GnRH treatment did not affect the CPR. In conclusion, LIP was effective in stimulating MY in heifers, and the IMI prevalence decreased with ATBS treatment. Also, the use of GnRH did not affect the FC regression, cyclicity at 45 DIM, and CPR.(AU)

Este estudo avaliou a (i) eficácia da associação entre antibioticoterapia injetável e selante interno de tetos (ATBS) na produção de leite (PL), contagem de células somáticas (CCS), e prevalência de infecções intramamárias (IIM); e (ii) eficácia do hormônio liberador de gonadotrofina (GnRH) na resolução de cistos foliculares (CFs), ciclicidade ao 45º dia em lactação (DEL) e taxa de prenhez cumulativa (TPC) em novilhas submetidas a um protocolo de indução de lactação (PIL). Um total de 114 novilhas mestiças (Holandês × Jersey), com 34,7 ± 4,8 meses e 439 ± 56,35 kg foram submetidas ao PIL. No 5º dia do PIL, as novilhas receberam: (i) ATBS (n = 57) com 7 mg/kg de norfloxacina associada ao selante interno de tetos e (ii) Controle 1 (n = 57; CONT1) sem tratamento. A lactação teve início no 21º dia do PIL e no 15º DEL, foram diagnosticados CFs e 106 novilhas foram agrupadas em dois grupos de tratamento com 53 novilhas em cada: (i) GnRH (5 mL de GnRH injetável) e (ii) Controle 2 (CONT2; sem tratamento). Das 114 novilhas inicialmente induzidas, 83,33% (n = 95) responderam ao PIL com PL média de 15,19 kg/leite/d durante 22 semanas de lactação. Nos primeiros 14 DEL a prevalência de IIM foi de 18% e 28% para as novilhas tratadas com ATBS e CONT1, respectivamente. Além disso, estafilococos coagulase negativa foram o grupo de patógenos mais frequentemente isolados. Quartos mamários tratados com ATBS tiveram menor risco (0,56) de IIM e menor CCS do que CONT1. A ciclicidade a 45 DEL foi de 68% (ATBS) e 35% (CONT1), e 57% e 46% para os animais no GnRH e CONT2. A TPC foi de 60% no grupo ATBS e 89% no CONT1, porém o tratamento com GnRH não afetou a TPC. Em conclusão, o PIL foi eficaz em estimular a PL em novilhas tardias e a prevalência de IIM diminiuiu com o tratamento ATBS. Além disso, o uso de GnRH não afetou a regressão de CF, ciclicidade em 45 DEL e a TPC.(AU)

[Development of Prediction System for Drug Absorption after Intranasal Administration Incorporating Physiologic Functions of Nose -Estimation of in Vivo Drug Permeation through Nasal Mucosa Using in Vitro Membrane Permeability].

The nasal drug application has drawn much attention as the strategy for the delivery route of many drug modalities such as the poorly absorbed drugs, peptides, nucleic acid, and central nervous system drugs. The absorption of drug after intranasal (IN) application depends on the nasal residence time of applied drug, affected by mucociliary clearance (MC). MC is a decisive factor in the nasal absorption of drug. We describe the establishment of in vitro evaluation system of nasal MC via the moving velocity of a marker particle on nasal mucosa, and the development of the pharmacokinetic model to which in vitro parameters on nasal MC was incorporated to enable the prediction of drug absorption after IN application. Moreover, the pharmacokinetics of norfloxacin after IN application was investigated using MC-modified rats pretreated with MC modulators. Nasal absorption fluctuated due to changes in the nasal residence time of drug in response to changes in MC. The prediction system enables quantitative evaluation of changes in drug absorption associated with MC fluctuations. In addition, for a precise prediction system for drug absorption after IN application from the drug absorption model, the relationships between in vitro drug permeability through Calu-3 layers, in vivo transnasal permeation of drug and in vivo bioavailability after IN application were evaluated. The significant correlations between these parameters were obtained, suggesting that transnasal permeability and drug absorption after IN application can be predicted from in vitro membrane permeability.

A VigiBase descriptive study of fluoroquinolone induced disabling and potentially permanent musculoskeletal and connective tissue disorders.

Recent drug safety concerns described fluoroquinolone (FQ)-induced serious musculoskeletal reactions. The objective of this study was to characterize reports with FQ-associated disabling musculoskeletal disorders, from VigiBase. The analysis included all FQ-induced musculoskeletal and connective tissue disorders adverse drug reaction (ADR) reports (up to July-2019), (disabling/incapacitating, or recovered/resolved with sequelae or fatal). We described aspects like reporter, suspected FQs, ADRs, associated corticosteroid therapy. We also looked into the disproportionality data in terms of proportional reporting ratio (PRR) and information component (IC) values. A total of 5355 reports with 13,563 ADRs and 5558 FQs were reported. The majority of reports were for patients aged 18-64 (62.67%), and the female gender prevailed (61.76%). Consumers reported almost half (45.99%), with a peak in reporting rates in 2017. Top reported ADRs were arthralgia (16.34%), tendonitis (11.04%), pain in extremity (9.98%), tendon pain (7.63%), and myalgia (7.17%). Top suspected FQs were levofloxacin (50.04%), ciprofloxacin (38.41%), moxifloxacin (5.16%), ofloxacin (3.17%) and norfloxacin (1.01%). For these, FQs-ADR association was supported by the disproportionality analysis. Corticosteroids were associated with about 7% of tendon related reports. The results augment the existing data on FQs safety concerns, specifically their potential effect on the musculoskeletal system.

Co-delivery of norfloxacin and tenoxicam in Ag-TiO2/poly(lactic acid) nanohybrid.

A nanohybrid formulation of silver­titanium dioxide nanoparticles/poly(lactic acid) (Ag-TiO2/PLA) was designed for Norfloxacin/Tenoxicam (NOR/TENO) targeted delivery to maximize the bioavailability and minimize the side effects of the drugs. Ag-TiO2 nanoparticles were prepared via Stober method. NOR, TENO and a mixture of NOR/TENO (NT) were loaded onto Ag-TiO2 nanoparticles and coated by PLA via solution casting. The physical interaction between the drugs and carrier was confirmed by Fourier-transform infrared (FTIR) analysis. X-ray diffraction (XRD) demonstrated that Ag-TiO2 consists of a cubic phase of Ag with two phases of TiO2 (anatase and brookite). Ag nanoparticle fine spots coated with TiO2 were collected to form spheres averaging at 100 nm in size. In-vitro release behavior of drugs was studied at different pH (5.4, 7.4) and the release of drug from NT/Ag-TiO2/PLA was faster at pH 7.4. Gram-positive and Gram-negative bacteria were used to investigate antibacterial properties of the nanohybrid. Cytotoxicity of the nanohybrid using an MTT assay was studied against different tumor and normal cell lines. It was found that NT/Ag-TiO2/PLA has an excellent cytotoxic effect against various bacterial cells and tumor cell lines. In addition, antioxidant properties of the nanohybrids were tested using ABTS method and the nanohybrid showed moderate antioxidant activity.

Natural halloysite nanotubes /chitosan based bio-nanocomposite for delivering norfloxacin, an anti-microbial agent in sustained release manner.

Applying nanotechnology to deliver drug could result in several benefits such as prolong duration of action, enhancement in overall bioavailability, targeting to specific site, low initial loading dose require, systemic stability enhancement etc. Halloysite is one of those clay minerals showing maximum effectiveness when consider as a nano drug carriers for different kind applications. Here, we have used norfloxacin as the model drug for loading into halloysite nanotube (HNT) for its anti-bacterial activity. Norfloxacin was loaded into halloysites by vacuum operation and sonication. The nanotubes were evaluated using X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), scanning electron microscopy (SEM), optical microscopy, water absorption studies, cytotoxicity studies, antimicrobial studies and in vitro diffusion studies. SEM, FT-IR and XRD analysis data showed that the norfloxacin was successfully loaded into nanotubes. TEM analysis confirmed loading of norfloxacin in halloysites' lumen. The halloysite/chitosan nanocomposites were prepared by solvent casting and freeze-drying method. SEM analysis revealed compact and rugged surface of nanocomposites due to existing norfloxacin loaded halloysite. FTIR and XRD confirmed formation of nanocomposite. The nanocomposites showed good antimicrobial effect and good biocompatibility in cytotoxicity study. The in-vitro release studies revealed that halloysite/chitosan nanocomposites were able to sustain the drug release. Also, the nanocomposites were stable in various humidity conditions. Therefore, all the outcomes suggest that the prepared nanocomposites can provide enhanced therapeutic benefits and they can be very potential nano vehicle for sustaining drug delivery.

The pandanus tectorius fruit extract (PTF) modulates the gut microbiota and exerts anti-hyperlipidaemic effects.

BACKGROUND: The gut microbiota plays a key role in the maintenance of human health and mediates the beneficial effects of natural products including polyphenols. Previous studies have demonstrated that the polyphenol-rich Pandanus tectorius fruit extract (PTF) was effective in ameliorating high-fat diet (HFD)-induced hyperlipidaemia, and polyphenols can significantly change the structure of the gut microbiota. PURPOSE: In this study, we assessed whether the modulation of the gut microbiota plays a key role in the PTF-induced anti-hyperlipidaemic effects. METHODS: Male C57BL/6 J mice were induced with hyperlipidaemia by consuming a high-fat diet (HFD) for 4 weeks. Then, the mice were orally administered PTF, antibiotics (ampicillin+ norfloxacin), PTF+antibiotics or vehicle for another 6 weeks. Body weights and 24-h food intake were assessed weekly. At the end of the experiment, fresh stools were collected for 16S RNA pyrosequencing, and blood and liver and fat tissue were collected for pharmacological analysis. RESULTS: PTF was effective in ameliorating high-fat diet (HFD)-induced hyperlipidaemia and significantly changed the structure of the gut microbiota. However, the anti-hyperlipidaemic effect of PTF was not influenced by the co-treatment with antibiotics (ampicillin+norfloxacin). A microbiological analysis of the gut microbiotas revealed that PTF selectively enhanced the relative abundance of Lactobacillus and decreased the relative abundance of Bacteroides and Alistipes. A correlation analysis between biochemical indexes and individual taxon showed that Lactobacillus was negatively associated with serum lipids and glucose while Bacteroides and Alistipes were positively associated with serum lipids and glucose. The modulatory effect of PTF on Lactobacillus, Bacteroides and Alistipes was not disturbed by the administration of antibiotics. CONCLUSION: These results demonstrated that the polyphenol-rich PTF as a unique gut microbiota modulating agent and highlighted the richness of Lactobacillus and the decreased abundance of Bacteroides and Alistipes as an effective indicator of the therapeutic effect of medicinal foods on hyperlipidaemia.

Norfloxacin Induced Recurrent Fixed Drug Eruption in a self Treated Adult Female Patient - A Case Report.

BACKGROUND: Fixed drug eruption is a clinical entity occurring at the same site each time the drug is administered. They are usually found on lips, genitalia, abdomen, and legs but can occur at any location. The eruptions usually occur within hours of administration of the drug and resolves spontaneously. Most common drugs causing them include antimicrobials. Fluroquinolones especially norfloxacin is commonly used in the treatment of gastrointestinal infections. Cutaneous adverse drug reactions are very rare with norfloxacin. CASE REPORT: In this case report, a young female, soon after taking Nofloxacin tablet, developed a blister with erythema and itching after self treatment for urinary tract infection. It got cured after stopping the drug and taking treatment from a dermatologist. It resolved as a hyper-pigmented scar. She experienced a similar episode of drug eruption on the same site when she again self medicated herself with Norfloxacin for diarrhoea. This time the reaction occurred within few hours and resolved with hyperpigmentation after medication. She was advised not to indulge in self-treatment in future. Suspecting association between the drug and the rash was confirmed and a diagnosis of Norfloxacin induced fixed drug eruption was made. CONCLUSION: Causality assessment by Naranjo's algorithm revealed a definite relationship between the cutaneous adverse drug reaction and the offending drug.

The influence of three antibiotics on the growth, intestinal enzyme activities, and immune response of the juvenile sea cucumber Apostichopus japonicus selenka.

The global abuse and misuse of antibiotics in the treatment and prevention of bacterial infections has resulted in the ubiquitous existence of these drugs in aquatic environments, which causes frequent antimicrobial resistance and pollution in ecosystems. However, the chronic effects of antimicrobial agents on aquatic animal growth and health have not been fully evaluated. In the present study, three typical antibiotics (tetracycline, erythromycin, and norfloxacin) were administered orally to juvenile sea cucumbers Apostichopus japonicus for 45 days, to mimic the long-term use of antibiotics. As a result, tetracycline and erythromycin promoted the growth and digestive activity of lipase, pepsin, and trypsin, but norfloxacin did not show significant prompting effect on digestive activity and even retarded the weight gain of the sea cucumbers. The mortality was higher in antibiotic treated groups between the 2nd and 4th days after challenge with Vibrio splendidus. At the same time, lower immune-related parameters were found in antibiotic feeding juveniles, suggesting that the use of antibiotics might weaken the immune defense system of sea cucumbers. This study revealed that antibiotic administration could facilitate the growth of sea cucumbers to varying degrees yet coupled with high risks of impaired immune function and compromised disease resistance.

Vitamin E Increases Antimicrobial Sensitivity by Inhibiting Bacterial Lipocalin Antibiotic Binding.

Burkholderia cenocepacia is an opportunistic Gram-negative bacterium that causes serious respiratory infections in patients with cystic fibrosis. Recently, we discovered that B. cenocepacia produces the extracellular bacterial lipocalin protein BcnA upon exposure to sublethal concentrations of bactericidal antibiotics. BcnA captures a range of antibiotics outside bacterial cells, providing a global extracellular mechanism of antimicrobial resistance. In this study, we investigated water-soluble and liposoluble forms of vitamin E as inhibitors of antibiotic binding by BcnA. Our results demonstrate that in vitro, both vitamin E forms bind strongly to BcnA and contribute to reduce the MICs of norfloxacin (a fluoroquinolone) and ceftazidime (a ß-lactam), both of them used as model molecules representing two different chemical classes of antibiotics. Expression of BcnA was required for the adjuvant effect of vitamin E. These results were replicated in vivo using the Galleria mellonella larva infection model whereby vitamin E treatment, in combination with norfloxacin, significantly increased larva survival upon infection in a BcnA-dependent manner. Together, our data suggest that vitamin E can be used to increase killing by bactericidal antibiotics through interference with lipocalin binding.IMPORTANCE Bacteria exposed to stress mediated by sublethal antibiotic concentrations respond by adaptive mechanisms leading to an overall increase of antibiotic resistance. One of these mechanisms involves the release of bacterial proteins called lipocalins, which have the ability to sequester antibiotics in the extracellular space before they reach bacterial cells. We speculated that interfering with lipocalin-mediated antibiotic binding could enhance the efficacy of antibiotics to kill bacteria. In this work, we report that when combined with bactericidal antibiotics, vitamin E contributes to enhance bacterial killing both in vitro and in vivo. This adjuvant effect of vitamin E requires the presence of BcnA, a bacterial lipocalin produced by the cystic fibrosis pathogen Burkholderia cenocepacia Since most bacteria produce lipocalins like BcnA, we propose that our findings could be translated into making novel antibiotic adjuvants to potentiate bacterial killing by existing antibiotics.

Binary and ternary complexes of norfloxacin to improve the solubility of the active pharmaceutical ingredient.

AIM: Binary and ternary complexes with hydroxypropyl-ß-cyclodextrin (HPßCD), using glutamic acid (GA), proline or lysine as the third component, were developed to increase the solubility and the dissolution rate of norfloxacin (NOR). METHODS/RESULTS: Complexation was evaluated by phase solubility studies, obtaining the highest NOR solubility with GA and HPßCD. Thermal analysis suggested that different kinds of interactions occur among NOR, HPßCD and each amino acid, and when the systems were prepared by kneading or by means of freeze-drying technique. Dissolution studies, performed on simulated gastric fluid and subsequent simulated intestinal fluid, showed the highest rate of NOR from NOR-HPßCD-GA. CONCLUSION: NOR:HPßCD:GA was the best approach for improving the bioavailability of NOR.

Quantitative Estimation of the Effect of Nasal Mucociliary Function on in Vivo Absorption of Norfloxacin after Intranasal Administration to Rats.

Nasal drug delivery has attracted significant attention as an alternative route to deliver drugs having poor bioavailability. Large-molecule drugs, such as peptides and central nervous system drugs, would benefit from intranasal delivery. Drug absorption after intranasal application depends on the nasal retention of the drug, which is determined by the nasal mucociliary clearance. Mucociliary clearance (MC) is an important determinant of the rate and extent of nasal drug absorption. The aim of the present study was to clarify the effect of the changes in MC on in vivo drug absorption after nasal application, and to justify the pharmacokinetic model to which the MC parameter was introduced, to enable prediction of bioavailability after intranasal administration. The pharmacokinetics of norfloxacin (NFX) after intranasal administration were evaluated following the modification of nasal MC by pretreatment with the MC inhibitors propranolol and atropine and the MC enhancers terbutaline and acetylcholine chloride. From the relationship between nasal MC and bioavailability after nasal application, prediction of drug absorption was attempted on the basis of our pharmacokinetic model. Propranolol and atropine enhanced the bioavailability of NFX by 90 and 40%, respectively, while the bioavailability decreased by 30% following terbutaline and 40% following acetylcholine chloride. As a result of changes in the MC function, nasal drug absorption was changed depending on the nasal residence time of the drug. On the basis of our pharmacokinetic model, the nasal drug absorption can be precisely predicted, even when the MC is changed. This prediction system allows the quantitative evaluation of changes in drug absorption due to changes in nasal MC and is expected to contribute greatly to the development of nasal formulations.

Effects of Long-term Norfloxacin Therapy in Patients With Advanced Cirrhosis.

BACKGROUND & AIMS: There is debate over the effects of long-term oral fluoroquinolone therapy in patients with advanced cirrhosis. We performed a randomized controlled trial to evaluate the effects of long-term treatment with the fluoroquinolone norfloxacin on survival of patients with cirrhosis. METHODS: We performed a double-blind trial of 291 patients with Child-Pugh class C cirrhosis who had not received recent fluoroquinolone therapy. The study was performed at 18 clinical sites in France from April 2010 through November 2014. Patients were randomly assigned to groups given 400 mg norfloxacin (n = 144) or placebo (n = 147) once daily for 6 months. Patients were evaluated monthly for the first 6 months and at 9 months and 12 months thereafter. The primary outcome was 6-month mortality, estimated by the Kaplan-Meier method, censoring spontaneous bacterial peritonitis, liver transplantation, or loss during follow-up. RESULTS: The Kaplan-Meier estimate for 6-month mortality was 14.8% for patients receiving norfloxacin and 19.7% for patients receiving placebo (P = .21). In competing risk analysis that took liver transplantation into account, the cumulative incidence of death at 6 months was significantly lower in the norfloxacin group than in the placebo group (subdistribution hazard ratio, 0.59; 95% confidence interval, 0.35-0.99). The subdistribution hazard ratio for death at 6 months with norfloxacin vs placebo was 0.35 (95% confidence interval, 0.13-0.93) in patients with ascites fluid protein concentrations <15 g/L and 1.39 (95% confidence interval, 0.42-4.57) in patients with ascites fluid protein concentrations ≥15 g/L. Norfloxacin significantly decreased the incidence of any and Gram-negative bacterial infections without increasing infections caused by Clostridium difficile or multiresistant bacteria. CONCLUSIONS: In a randomized controlled trial of patients with advanced cirrhosis without recent fluoroquinolone therapy, norfloxacin did not reduce 6-month mortality, estimated by the Kaplan-Meier method. Norfloxacin, however, appears to increase survival of patients with low ascites fluid protein concentrations. ClinicalTrials.gov ID: NCT01037959.

Daily Norfloxacin vs. Weekly Ciprofloxacin to Prevent Spontaneous Bacterial Peritonitis: A Randomized Controlled Trial.

OBJECTIVES: For the prevention of spontaneous bacterial peritonitis (SBP) in cirrhotic patients with ascites, norfloxacin 400 mg per day is recommended as a standard regimen. This study aims to investigate whether ciprofloxacin once weekly administration is not inferior to norfloxacin once daily administration for the prevention of SBP. METHODS: This is an investigator-initiated open-label randomized controlled trial conducted at seven tertiary hospitals in South Korea. Liver cirrhosis patients with ascites were screened, and enrolled in this randomized controlled trial if ascitic protein ≤1.5 g/dL or the presence of history of SBP. Ascitic polymorphonucleated cell count needed to be <250/mm3. Patients were randomly assigned into norfloxacin daily or ciprofloxacin weekly group, and followed-up for 12 months. Primary endpoint was the prevention of SBP. RESULTS: One hundred twenty-four patients met enrollment criteria and were assigned into each group by 1:1 ratio (62:62). Seven patients in the norfloxacin group and five patients in the ciprofloxacin group were lost to follow-up. SBP developed in four patients (4/55) and in three patients (3/57) in each group, respectively (7.3% vs. 5.3%, P = 0.712). The transplant-free survival rates at 1 year were comparable between the groups (72.7% vs. 73.7%, P = 0.970). Incidence of infectious complication, hepatorenal syndrome, hepatic encephalopathy, and variceal bleeding rates were not significantly different (all P = ns). The factors related to survival were models representing underlying liver function. CONCLUSION: Once weekly ciprofloxacin was as effective as daily norfloxacin for the prevention of SBP in cirrhotic patients with ascites.

Cyclodextrin based nanosponge of norfloxacin: Intestinal permeation enhancement and improved antibacterial activity.

Nanosponges are a novel class of hyperbranched cyclodextrin-based nanostructures that exhibits remarkable potential as a drug host system for the improvement in biopharmaceutical properties. This work aims the development of cyclodextrin-based nanosponge of norfloxacin to improve its physicochemical characteristics. ß-cyclodextrin was used as base and diphenyl carbonate as crosslinker agent at different proportions to produce nanosponges that were evaluated by in vitro and in vivo techniques. The proportion cyclodextrin:crosslinker 1:2 M/M was chosen due to its higher encapsulation efficiency (80%), revealing an average diameter size of 40 nm with zeta potential of -19 mV. Norfloxacin-loaded nanosponges exhibited higher passage of norfloxacin in comparison to norfloxacin drug alone by Ussing chamber method. The nanosponge formulation also revealed a mucoadhesive property that could increase norfloxacin absorption thus improving its antibiotic activity in an in vivo sepsis model. Therefore, nanosponges may be suitable carrier of norfloxacin to maximize and facilitate oral absorption.

Low-dose Norfloxacin-treated leptospires induce less IL-1ß release in J774A.1 cells following discrepant leptospiral gene expression.

Currently, accumulating evidence is challenging subtherapeutic therapy. Low-dose Norfloxacin (Nor) has been reported to suppress the immune response and worsen leptospirosis. In this study, we investigated the influence of low-dose Nor (0.03 µg/ml, 0.06 µg/ml, 0.125 µg/ml) on leptospiral gene expression and analyzed the immunomodulatory effects of low-dose Nor-treated leptospires in J774A.1 cells. To study the expression profiles of low-dose Nor-treated leptospires, we chose LipL71/LipL21 as reference genes determined by the geNorm applet in this experiment. The results showed that low-dose Nor up-regulated the expression of FlaB and inhibited the expression of 16S rRNA, LipL32, LipL41, Loa22, KdpA, and KdpB compared with the untreated leptospires. These results indicated that low-dose Nor could regulate leptospiral gene expression. Using RT-PCR, the gene expression of IL-1ß and TNF-α in J774A.1 cells was detected. Nor-treated leptospires induced higher expression levels of both IL-1ß and TNF-α. However, when analyzed by ELISA, the release of mature IL-1ß was reduced compared with that observed in cells induced with no Nor-treated leptospires, although the TNF-α protein level showed no significant change. Our study indicated that the gene expression of leptospires could be modulated by low-dose Nor, which induced less IL-1ß release in J774A.1 cells.

Novel naphthalimide nitroimidazoles as multitargeting antibacterial agents against resistant Acinetobacter baumannii.

AIM: The increasing emergence of resistant bacteria imposed an urgent request to discover novel antibacterial agents. This work was to develop naphthalimide nitroimidazoles as potentially antibacterial agents. Results/methodology: Compound 9e showed the strong antibacterial activity (minimal inhibitory concentration = 0.013 µmol/ml) against resistant Acinetobacter baumannii (A. baumannii) with rapid killing effect and no obvious triggering of the development of resistance. Its combination use with chloromycin, norfloxacin or clinafloxacin improved the antibacterial potency. It could not only effectively permeate membrane of resistant A. baumannii bacteria, but also intercalate into resistant A. baumannii DNA to form 9e-DNA complex. The interaction with bacterial DNA gyrase B was driven by hydrogen bonds. CONCLUSION: Compound 9e should be a potentially multitargeting antibacterial agent against resistant A. baumannii.

Frequency of enterotoxins, toxic shock syndrome toxin-1, and biofilm formation genes in Staphylococcus aureus isolates from cows with mastitis in the Northeast of Brazil.

Staphylococcus aureus is among the microorganisms more frequently associated with subclinical bovine mastitis. S. aureus may produce several virulence factors. This study aimed at determining the frequency of virulence factors such as enterotoxins, toxic shock syndrome toxin 1, and ica adhesion genes. In addition, we assessed antimicrobial drug resistance in S. aureus isolated from clinical and subclinical cases of mastitis. A total of 88 cows with clinical or subclinical mastitis were sampled, resulting in 38 S. aureus isolates, from which 25 (65.78%) carried toxin genes, including seb, sec, sed, tst, and icaD adhesion gene. These S. aureus isolates belong to 21 ribotypes and three S. aureus strains belonged to the same ribotype producing ica adhesion gene. Approximately 90% of S. aureus strains obtained in our study demonstrated multiple resistance to different antimicrobial agents. The most efficacious antimicrobial agents against the isolates were gentamicin, amoxicillin, and norfloxacin. Gentamicin was the most efficacious agent inhibiting 78.95% of the S. aureus isolates. The least efficacious were penicillin, streptomycin, and ampicillin. Our results can help in understanding the relationship between virulence factors and subclinical mastitis caused by S. aureus. Further research about diversity of S. aureus isolates and genes responsible for the pathogenicity of subclinical mastitis is essential.

Pharmacokinetics of norfloxacin after intravenous, intramuscular and subcutaneous administration to rabbits.

The disposition kinetics of norfloxacin, after intravenous, intramuscular and subcutaneous administration was determined in rabbits at a single dose of 10 mg/kg. Six New Zealand white rabbits of both sexes were treated with aqueous solution of norfloxacin (2%). A cross-over design was used in three phases (2 × 2 × 2), with two washout periods of 15 days. Plasma samples were collected up to 72 hr after treatment, snap-frozen at -45°C and analysed for norfloxacin concentrations using high-performance liquid chromatography. The terminal half-life for i.v., i.m. and s.c. routes was 3.18, 4.90 and 4.16 hr, respectively. Clearance value after i.v. dosing was 0.80 L/h·kg. After i.m. administration, the absolute bioavailability was (mean ± SD) 108.25 ± 12.98% and the Cmax was 3.68 mg/L. After s.c. administration, the absolute bioavailability was (mean ± SD) 84.08 ± 10.36% and the Cmax was 4.28 mg/L. As general adverse reactions were not observed in any rabbit and favourable pharmacokinetics were found, norfloxacin at 10 mg/kg after i.m. and s.c. dose could be effective in rabbits against micro-organisms with MIC ≤0.14 or 0.11 µg/mL, respectively.

Hybrid nanoparticles for the topical delivery of norfloxacin for the effective treatment of bacterial infection produced after burn.

The present study was designed to investigate the solubility and penetrability of norfloxacin after the topical application of developed lipid-polymer hybrid nanoparticle (LPN) formulation. The core shell of the LPNs formulation was composed of poly (lactic-co-glycolic acid) that is highly lipophilic in nature, thus control the release of drug. The developed formulations were characterised for size, shape (transmission electron microscopy [TEM], scanning electron microscopy [SEM], and atomic force microscopy), entrapment efficiency, Fourier transform infra-red (FTIR) spectroscopy, differential scanning calorimetry (DSC) and thermo gravimetric analysis (TGA). Moreover, in vitro skin permeation studies were performed to determine release profile of the drug. Norfloxacin loaded nanoparticles retained there antimicrobial efficacy against Staphylococcus aureus and Pseudomonas aeruginosa. Stability study was suggested that the suitable storage condition should be at 4 ± 2 °C/60 ± 5% RH for the LPNs. Therefore, these nanoparticles showed a safe and effective long-lasting approach for long treatment of bacterial infections due to burn.

Low-dose norfloxacin and ciprofloxacin therapy worsen leptospirosis in hamster.

Antibiotics play an important role in the treatment of leptospirosis. Many antibiotics at appropriate concentrations improved the survival rate and alleviated tissue injury, while, when dosing strategies fall below subtherapeutic levels, worse therapeutic effects are seen. In the present study, we investigated the efficacy of low-dose norfloxacin (10, 20 and 30 mg/kg) and ciprofloxacin (1, 2 and 5 mg/kg) against leptospirosis in a hamster model using Leptospira interrogans serovar Icterohaemorrhagiae. The histopathology and bacterial loads of target organs (liver, kidney and lung) were also studied by treatment with norfloxacin at the dose of 10 mg/kg in this model. Using RT-PCR, the expression of inflammatory factor IL-1ß and TNF-α was analyzed by comparing the norfloxacin and untreated group. All untreated animals, serving as a negative control, displayed 50% survival rate, while hamsters treated with norfloxacin at the dose of 10 and 20 mg/kg and ciprofloxacin at the dose of 1 and 2 mg/kg showed a lower survival rate than the untreated group. Furthermore, norfloxacin at the dose of 10 mg/kg increased bacterial loads and aggravated tissue injury of target organs. The delayed induction of IL-1ß and TNF-α was found in tissues of norfloxacin group. Our study indicates an increased risk associated with low-dose norfloxacin and ciprofloxacin in leptospirosis.