oxytetracycline--anhydrous and Labyrinthitis

The aims of this field trial were to describe the clinical-pathologic findings in calves with otitis media (OM) and media-interna (OMI), to evaluate, through the development of a scoring system, the effectiveness of a standardized therapeutic protocol, and to identify the causative pathogens and their possible correlation with concurrent respiratory disease. All animals underwent physical and neurological examinations at three experimental time points: at diagnosis/beginning of treatment (T0), 1 week (T1) and 2 weeks (T2) after therapy was started, respectively. Follow-up telephone interviews with animal owners were conducted 1 month later. The therapeutic protocol consisted of tulathromycin (Draxxin®; Zoetis), oxytetracycline hydrochloride (Terramicina 100®; Zoetis), and carprofen (Rimadyl®; Zoetis).. Twenty-two calves were enrolled. Physical and otoscopic examination at T0 revealed monolateral and bilateral otorrhea in 16 and 6 calves, respectively, with peripheral vestibular system involvement in calves presenting with neurological signs (n = 17; 77 %). A significant improvement of clinical and neurological scores was observed in 20 (90 %) calves, a full recovery in only 1 (5 %). One calf worsened between T0 and T1 and it was removed from the study. None of the other animals showed a worsening of clinical conditions and/or required further treatments at one month follow up. Mycoplasma bovis was isolated in 89 % of the affected ears either alone or together with P. multocida (n = 5), Streptococcus spp. (n = 1), Staphylococcus spp. (n = 1), and Pseudomonas spp. (n = 1). M. bovis either alone or together with these bacteria was also isolated from the upper and/or lower respiratory tract in 19 (86 %) calves.. This is the first prospective study to evaluate the effectiveness of a standardized therapeutic protocol for the treatment of OM/OMI in calves. The therapy led to clinical improvement in the majority of the calves. Persistence of mild clinical-neurological signs did not compromise productive performance. The numerical scoring system for clinical and neurological signs permitted objective evaluation of response to therapy. M. bovis was the pathogen most often isolated. This finding should be considered in the treatment of OM/OMI in calves. Moreover, respiratory tract infection should not be underrated, since it is one of the major risk factors for the development of OM/OMI.

Topics: Animals; Anti-Bacterial Agents; Anti-Inflammatory Agents, Non-Steroidal; Carbazoles; Cattle; Cattle Diseases; Disaccharides; Female; Heterocyclic Compounds; Labyrinthitis; Male; Otitis Media; Oxytetracycline

Oxytetracycline and ilomastat are inhibitors of matrix metalloproteinases (MMPs). Their efficacy in protecting against cochlear damage induced by the intratympanic instillation of lipopolysaccharide (LPS), as a means of inducing labyrinthitis, was investigated.. Experiments were performed in 21 young male guinea pigs. Intratympanic instillation of LPS was done in the control group (n=7). Intratympanic instillation of oxytetracycline or ilomastat was done after LPS instillation in the experimental group. Measurements of auditory brainstem response (ABR) and cochlear blood flow (CBF) were performed. The organ of Corti was evaluated by field emission scanning electron microscopy (FE-SEM). The blood-labyrinth barrier (BLB) integrity was evaluated with Evans blue uptake. Gelatin zymography was used to assess the expression of active MMP-2 and MMP-9.. Ears treated with MMP inhibitors were significantly protected from hearing loss compared to the LPS group. In LPS group, there was a significant decrease of CBF. However, experimental group displayed a statistically significant recovery of CBF. FE-SEM revealed hair cell damage in the LPS-treated group, but hair cells presented a normal appearance in MMP inhibitors. The LPS group showed a marked increase of Evans blue extravasation in the cochlea. However, MMP inhibitors significantly reduced the BLB opening. Active MMP-9 was expressed in the LPS group. Treatment with MMP inhibitors attenuated active MMP-9 expression.. The MMP inhibitors oxytetracycline and ilomastat protect from cochlear lateral wall damage caused by LPS-induced labyrinthitis.

Topics: Animals; Anti-Bacterial Agents; Cochlea; Disease Models, Animal; Evoked Potentials, Auditory, Brain Stem; Guinea Pigs; Hearing Loss; Hydroxamic Acids; Indoles; Instillation, Drug; Labyrinthitis; Lipopolysaccharides; Male; Matrix Metalloproteinase Inhibitors; Oxytetracycline