BLOOD CONCENTRATION OF MARBOFLOXACIN AND ITS IN VIVO EFFECT IN YELLOW-BELLIED SLIDER TURTLES (TRACHEMYS SCRIPTA SCRIPTA), AFTER A SINGLE INTRACOELOMIC INJECTION AT THREE DOSE RATES

Marbofloxacin is a commonly used antibiotic drug to treat bacterial infections in pet animals. Similarly to other fluoroquinolones, marbofloxacin is subject to the emerging problem of antimicrobial resistance. Thus, it is necessary to use PK/PD integration and modeling to minimize the selection of resistant mutants of bacteria and extend the useful life of antimicrobial agents, including marbofloxacin. This study evaluated the pharmacokinetics and the in vivo efficacy of marbofloxacin in Trachemys scripta scripta after a single intracoelomic injection. Three groups of 8 healthy adult turtles were each treated with 0.4, 2 and 10 mg/kg of marbofloxacin, respectively. Blood samples and rectal swabs were collected to measure marbofloxacin concentrations in serum (using an HPLC-FL validated method) and to evaluate in vitro antimicrobial susceptibility (using Kirby-Bauer Method), respectively. The PK profiles of marbofloxacin fit a bi-compartmental model and were dose dependent. The Tmax and half life ranged between 2.82–4.64 hours and 16.14–30.68 hours, respectively. Bacteria isolation showed the presence of both E. coli and Salmonella spp. Salmonella spp. was isolated only 48 hours after the administration of marbofloxacin and all strains were considered resistant. Results seem to suggest that even if marbofloxacin is able to reach considerable plasma concentrations, it can still be ineffective against bacteria that are potential animal and human pathogens