Pharmacokinetics of marbofloxacin administered via intravenous regional limb perfusion in dairy cows: evaluation of two different tourniquets

Clinical Efficacy of a Single Intravenous Regional Limb Perfusion with Marbofloxacin versus Ceftiofur Sodium to Treat Acute Interdigital Phlegmon in Dairy Cows

The objective of the study was to compare the clinical efficacy of a single antimicrobial intravenous regional limb perfusion (IVRLP) with marbofloxacin versus ceftiofur sodium to treat naturally occurring interdigital phlegmon (IP) in dairy cows. The study had a randomized parallel-group design. Forty lactating Friesian cows clinically diagnosed with acute IP were enrolled, assigned to one of two treatment groups, and received a single IVRLP with the antimicrobial drug selected (M: 0.67 mg/kg of marbofloxacin; C: 500 mg/animal of ceftiofur sodium). Clinical data for the severity of lameness, digital swelling and local lesion appearance were assessed at diagnosis and at 5, 10 and 15 days post-IVRLP. Clinical resolution was defined as digital swelling disappearance, locomotion score reduction of at least 2/5 points, healed or healing local lesion and no relapse at 15 days after IVRLP. The total daily milk yield of each cow on the day before the clinical detection, on the day of diagnosis and on the day of the clinical follow-up post-IVRLP were registered. Lameness, digital swelling and local lesion severity were not significantly different between groups at any time-point. In both groups, on the fifteenth day after treatment, 17/20 (85%) cows showed a positive outcome, with no significant difference (p > 0.05). The daily milk production of all cows was adversely affected by the clinical onset of IP and gradually returned to a normal level after IVRLP in both groups. These preliminary results support the hypothesis that a single antimicrobial IVRLP procedure, irrespective of the antimicrobial selected (ceftiofur vs. marbofloxacin), has a high success rate and restores milk yield in cases of dairy cattle with acute IP lameness.

Autologous platelet-rich plasma effects on Staphylococcus aureus-induced chondrocyte death in an in vitro bovine septic arthritis model

OBJECTIVE

To investigate the chondroprotective effects of autologous platelet-rich plasma (PRP), ampicillin-sulbactam (AmpS), or PRP combined with AmpS (PRP+AmpS) in an in vitro chondrocyte explant model of bovine Staphylococcus aureus-induced septic arthritis.

SAMPLE

Autologous PRP and cartilage explants obtained from 6 healthy, adult, nonlactating Jersey-crossbred cows.

ProcedureS

Autologous PRP was prepared prior to euthanasia using an optimized double centrifugation protocol. Cartilage explants collected from grossly normal stifle joints were incubated in synovial fluid (SF) alone, S aureus-inoculated SF (SA), or SA supplemented with PRP (25% culture medium volume), AmpS (2 mg/mL), or both PRP (25% culture medium volume) and AmpS (2 mg/mL; PRP+AmpS) for 24 hours. The metabolic activity, percentage of dead cells, and glycosaminoglycan content of cartilage explants were measured with a resazurin-based assay, live-dead cell staining, and dimethylmethylene blue assay, respectively. Treatment effects were assessed relative to the findings for cartilage explants incubated in SF alone.

RESULTS

Application of PRP, AmpS, and PRP+AmpS treatments significantly reduced S aureus-induced chondrocyte death (ie, increased metabolic activity and cell viability staining) in cartilage explants, compared with untreated controls. There were no significant differences in chondrocyte death among explants treated with PRP, AmpS, or PRP+AmpS.

CLINICAL RELEVANCE

In this in vitro explant model of S aureus-induced septic arthritis, PRP, AmpS, and PRP+AmpS treatments mitigated chondrocyte death. Additional work to confirm the efficacy of PRP with bacteria commonly associated with clinical septic arthritis in cattle as well as in vivo evaluation is warranted.

In vitro Elution of Penicillin, Ampicillin, Tetracycline, Tulathromycin, and Florfenicol From Plaster of Paris Beads

The objectives of this study were to report a recipe for making antibiotic impregnated Plaster of Paris (AI-PoP) beads using penicillin, ampicillin, tetracycline, tulathromycin, and florfenicol and to determine the in vitro elution rates of those antibiotics in the beads. The AI-PoP beads were made using Plaster of Paris powder, antibiotic, and water, cured for 24 h, sterilized by ethylene oxide, and stored up to 5 months before testing. For each antibiotic, 20 beads were combined with bovine serum in sterile tubes and incubated at 37°C on a rocker. Serum was replaced at intervals over the 14 days study period, and antibiotic concentrations were determined by high pressure liquid chromatography with mass spectrometry. Separately, in a proof-of-concept study, the growth of E. coli and T. pyogenes in eluent from 10 beads for each antibiotic was quantified by flow cytometry. Antibiotic was detected in AI-PoP bead eluent for 14 days for all but the ampicillin beads, for which antibiotic was detected for 8 days. The concentration of antibiotic in eluent was greater than the minimum inhibitory concentration (MIC) of tested bacteria for the entire study period for penicillin, tetracycline, tulathromycin, and florfenicol. The concentration of ampicillin remained greater than the MIC of E. coli for 4 days and T. pyogenes for 6 days. The colony forming units (CFU)/ml of live E. coli and T. pyogenes was reduced over a 72-h period by 1-3 log10 CFU, with the exception of tetracycline, which reduced CFU/ml of T. pyogenes by Collapse

Key Words

• Plaster of Paris
• antibiotics
• cattle
• elution
• wound infection

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Affiliation(s)

Paul Merkatoris Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
Jennifer Schleining Department of Large Animal Clinical Sciences, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, United States
Adam Krull Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
David Borts Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, IA, United States
Virginia Fajt Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine & Biomedical Sciences, Texas A&M University, College Station, TX, United States

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