In vitrosusceptibilities ofLeptospiraspp. andBorrelia burgdorferiisolates to amoxicillin, tilmicosin, and enrofloxacin

Abstract

Antimicrobial susceptibility testing was conducted with 6 different spirochetal strains (4 strains of Leptospira spp. and 2 strains of Borrelia burgdorferi) against 3 antimicrobial agents, commonly used in equine and bovine practice. The ranges of MIC and MBC of amoxicillin against Leptospira spp. were 0.05-6.25 µg/ml and 6.25-25.0 µg/ml, respectively. And the ranges of minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) of amoxicillin against B. burgdorferi were 0.05-0.39 µg/ml and 0.20-0.78 µg/ml, respectively. The ranges of MIC and MBC of enrofloxacin against Leptospira spp. were 0.05-0.39 µg/ml and 0.05-0.39 µg/ml, respectively. Two strains of B. burgdorferi were resistant to enrofloxacin at the highest concentration tested for MBC (≥100 µg/ml). Therefore, the potential role of tilmicosin in the treatment of leptospirosis and borreliosis should be further evaluated in animal models to understand whether the in vivo studies will confirm in vitro results. All spirochetal isolates were inhibited (MIC) and were killed (MBC) by tilmicosin at concentrations below the limit of testing (≤0.01 µg/ml).

Acute renal disease fromLeptospira interrogansin three yearlings from the same farm

“…Fluoroquinolones are bactericidal antibiotics with a relatively low MIC (<0.2 mg/l) against Leptospira (Murray and Hospenthal 2004). Enrofloxacin has good in vitro antimicrobial efficacy against Leptospira strains isolated from animal clinical cases (Kim et al 2006;Divers et al 2008). Based on these data, the 3 yearlings in this report were treated with penicillin and enrofloxacin.…”

Borrelia burgdorferiInfection and Lyme Disease in North American Horses: A Consensus Statement

“…Therefore, treatment recommendations have been based on in vitro B . burgdorferi antibiotic susceptibility, extrapolation from human treatment guidelines, available antibiotic pharmacokinetic data in horses, and a single treatment trial in experimentally infected ponies …”

Enrofloxacin concentrations in the vitreous of horses with equine recurrent uveitis (ERU) after repeated intravenous administration

“…Der Unterschied erreichte kein Signifikanzniveau. Die Enrofloxacinkonzentrationen, die mit dem Behandlungsregime dieser Untersuchung im Glaskörper erreicht wurden, lagen mit einem Mittelwert von 1,06 µg/ml (0,47-2,20 µg/ml) deutlich über den angegebenen Werten der von Kim et al (2006) angegebenen minimalen Hemmkonzentration und der minimalen bakteriziden Konzentration von Enrofloxacin gegen Leptospiren. Die in dieser Studie erreichten Enrofloxacinkonzentrationen im Glaskörper sprechen für eine Schädigung der Blutaugenschranke.…”