Uso de antimicrobiano nanoparticulado para o tratamento da mastite subcl?nica de ovelhas de corte no per?odo seco.

A inflama??o da gl?ndula mam?ria ? uma das principais causas de preju?zo na ovinocultura. Este estudo teve como objetivo investigar as taxas de cura do tratamento da mastite subcl?nica ap?s infus?o intramam?ria de princ?pio ativo antimicrobiano no momento da secagem, em formula??es convencional e nanoparticulada. Os rebanhos estavam localizados em S?o Carlos, S?o Paulo, Brasil. Analisou-se um total de 584 gl?ndulas mam?rias de 307 ovelhas de aptid?o para produ??o de carne. Triagem pr?via dos casos subcl?nicos de mastite foi efetuada por meio do California Mastitis Test (CMT) e/ou da contagem de c?lulas som?ticas (CCS). An?lises microbiol?gicas foram realizadas para confirma??o da etiologia infecciosa. As gl?ndulas mam?rias com mastite subcl?nica foram distribu?das em tr?s grupos: G1 (Controle; gl?ndulas mam?rias que n?o receberam tratamento antimicrobiano); G2 (gl?ndulas mam?rias em que foi administrado 100 mg de cloxacilina benzatina em estrutura convencional) e G3 (gl?ndulas mam?rias em que foi administrado 50 mg de cloxacilina benzatina em estrutura nanoencapsulada). O tratamento aplicado ao G3 mostrou-se mais eficiente (P=0,047) na cura de gl?ndulas mam?rias com mastite subcl?nica. O uso da cloxacilina nanoencapsulada no momento da secagem de ovelhas de corte auxilia no controle da mastite subcl?nica infecciosa e reduz os preju?zos consequentes.Inflammation of the mammary gland is one of the main causes of losses in sheep-rearing. This study aimed to investigate the cure rates from treating subclinical mastitis after intramammary infusion of active antimicrobial agents as conventional formulations or as nanoparticles, at the time when the ewes are being dried off. A total of 584 mammary glands in 307 ewes in meat-producing herds located in S?o Carlos, S?o Paulo, Brazil, were analyzed. Prescreening of subclinical mastitis cases was done using the California mastitis test (CMT) and/or the somatic cell count (SCC). Microbiological analyses were performed to confirm the infectious etiology. The mammary glands with subclinical mastitis were distributed into three groups: G1 (control; mammary glands that did not receive any antimicrobial treatment); G2 (mammary glands to which 100mg of benzathine cloxacillin in conventional form were administered); and G3 (mammary glands to which 50mg of benzathine cloxacillin in nanoparticulate form were administered). The treatment applied to G3 was more efficient (P=0.047) in curing mammary glands with subclinical mastitis. Use of cloxacillin nanoparticles at the time when the ewes are being dried off helps to control infectious subclinical mastitis and reduces consequential losses among meat-producing herds

Cloxacillin nanostructured formulation for the treatment of bovine keratoconjunctivitis.

Infectious bovine keratoconjunctivitis (IBK) is a widespread, contagious ocular disease that affects cattle, especially dairy breeds. The disease is caused by Gram-negative bacteria mainly Moraxella bovis, and its treatment consists of parenteral or topic antibiotic therapy. The topic treatment approach is used more commonly in lactating cows, to avoid milk disposal. However, treatment failures are common, because the antibiotic is removed during lacrimation. This study aimed to evaluate the susceptibility of commercial cloxacillin and evaluate the efficacy of nanostructured cloxacillin in clinical cases of IBK by Moraxella. The minimum inhibitory concentration (MIC) of nanoparticle cloxacillin nanocoated, the nanoparticle without the antibiotic and the commercial cloxacillin were determined in vitro with field samples of Moraxella ovis (5) and Moraxella bovis (5). The efficiency of nanoparticles was tested in three cows naturally infected that were treated with 1.0 mL (with 0.32 mg of nanostructured cloxacillin) for the ocular route. Moraxella bovis was isolated and identified by biochemical and molecular methods before the treatment. The animals were treated every 12 h for six days. The cure was considered by the absence of clinical symptoms and bacteria after treatment. The mucoadhesive nanoparticle-based formulation promoted clinical cure with a low number of doses of antibiotics, probably due to the maintenance of the MIC in the ocular mucosa for longer due to the mucoadhesive characteristics of the nanoparticle. The results indicate that the use of nanocoated cloxacillin is possible to control infectious bovine keratoconjunctivitis

Rela??o entre genes de fatores de virul?ncia em Staphylococcus spp. coagulase-negativos e a falha do tratamento antimicrobiano da mastite subcl?nica ovina.

Coagulase-negative Staphylococcus spp. (CNS) are the main microorganisms involved in ovine mastitis. Treatment at the end of lactation can contribute towards cure and prevention of subclinical cases during the subsequent lactation. However, virulence factors and resistance mechanisms presented by CNS can decrease cure rates. The aims of the study were to identify the species of CNS in milk of mastitic ewes with and without antimicrobial treatment, and to investigate the presence of genes relating to resistance of ?-lactam antimicrobials, formation of biofilms, production of enterotoxins and production of the toxic shock syndrome toxin. Cases of failure in the treatment were related with the presence/absence of the respective genes. Sixty sheep were divided into three groups: G1, without treatment; G2, animals treated via the intramammary route with 100mg of cloxacillin during drying off; and G3, sheep treated via the intramammary route with 50 mg of nanoparticulate cloxacillin. Milk samples were gathered during drying off and 15 and 30 days after the parturition of the subsequent lactation. The analyses to identify the species of CNS were carried out by means of the internal transcribe spacer technique and the investigation of the genes responsible for the virulence factors and resistance to oxacillin was performed using the polymerase chain reaction (PCR) technique. No sample was positive for the mecA gene. The only gene relating to production of enterotoxins was sec. Among the genes relating to production of biofilm, icaD was the only one identified in the three experimental groups. Staphylococcus warneri was the main species of CNS isolated during the pre and post-partum periods of the sheep. The species carrying genes relating to production of enterotoxins and biofilms were present in uncured sheep.Staphylococus spp. coagulase-negativos (SCN) est?o entre os principais micro-organismos envolvidos na mastite ovina. O tratamento ao final da lacta??o pode contribuir com a cura e a preven??o de casos subcl?nicos durante a lacta??o seguinte. Todavia, fatores de virul?ncia e mecanismos de resist?ncia apresentados por SCN podem reduzir as taxas de cura. Os objetivos desse estudo foram identificar as esp?cies de SCN no leite de ovelhas com mastite com e sem tratamento antimicrobiano e investigar a presen?a de genes relacionados com resist?ncia a antibi?ticos beta lact?micos, forma??o de biofilmes, produ??o de enterotoxinas e produ??o da toxina da s?ndrome do choque t?xico. Casos de falhas no tratamento foram relacionados com a presen?a/aus?ncia dos respectivos genes. Sessenta ovelhas foram divididas em tr?s grupos: G1, sem tratamento; G2, animais tratados via intramam?ria com 100mg de cloxacilina antes da secagem; e G3, ovelhas tratadas via intramam?ria com 50 mg de cloxacilina nanoparticulada. Amostras de leite foram obtidas durante a secagem e 15 e 30 dias depois do parto na lacta??o seguinte. As an?lises para identificar as esp?cies de SCN foram conduzidas por meio da t?cnica de Internal transcribe spacer e a investiga??o dos genes respons?veis pelos fatores de virul?ncia e resist?ncia ? oxacilina foi realizada usando a t?cnica rea??o em cadeia da polimerase. Nenhuma amostra foi positiva para o gene mecA. O ?nico gene relacionado com a produ??o de enterotoxinas foi o sec. Dentre os genes relacionados com a produ??o de biofilme, icaD foi o ?nico identificado nos tr?s grupos experimentais. Staphylococcus warneri foi a principal esp?cie de SCN isolada durante o pr? e p?s-parto. As esp?cies que apresentaram genes relacionados com a produ??o de enterotoxinas e biofilmes estavam presentes nas ovelhas n?o curadas

Cloxacillin benzathine-loaded polymeric nanocapsules : physicochemical characterization, cell uptake, and intramammary antimicrobial effect.

The present work shows the development and evaluation of the veterinary antibiotic cloxacillin benzathine (CLOXB) loaded into poly-?-caprolactone (PCL) nanocapsules (NC), as a potential new treatment strategy to manage bovine intramammary infections, such as mastitis. Staphylococcus aureus-induced mastitis is often a recurrent disease due to the persistence of bacteria within infected cells. CLOXB-PCL NC were prepared by interfacial deposition of preformed biodegradable polymer followed by solvent displacement method. The mean diameter of NC varied from 241 to 428?nm and from 326 to 375?nm, when determined by dynamic light scattering and by atomic force microscopy, respectively. The zeta potential of NC was negative and varied from ?28 to ?51?mV. In vitro release studies from the NC were performed in two media under sink conditions: PBS with 1% polyethylene glycol or milk. A reversed-phase HPLC method was developed to determine the NC entrapment efficiency and kinetics of CLOXB release from the NC. Free CLOXB dissolution occurred very fast in both media, while drug release from the NC was slower and incomplete (below 50%) after 9?h. CLOXB release kinetics from polymeric NC was fitted with the Korsmeyer-Peppas model indicating that CLOXB release is governed by diffusion following Fick's law. The fluorescence confocal microscopy images of macrophage-like J774A.1 cells reveal NC uptake and internalization in vitro. In addition, antimicrobial effect of the intramammary administration of CLOXB-PCL NC in cows with mastitis resulted in no clinical signs of toxicity and allowed complete pathogen elimination after treatment. The in vivo results obtained in this work suggest that CLOXB-PCL NC could be a promising formulation for the treatment of intramammary infections in cattle, considering their physicochemical properties, release profiles and effects on bovine mastitis control