In Vitro and Ex Vivo Levofloxacin Antibacterial Activity against Escherichia Coli Isolated from Domestic Rabbits

Activity: Talk or presentation types › Oral presentation

Description

Some Escherichia coli (E. coli) strains can be pathogenic to companion animals, including pet rabbits, causing potentially lethal diarrhoea. Levofloxacin (LVFX) is a fluoroquinolone antimicrobial, approved for human medicine and used off-label in veterinary medicine. LVFX antibacterial effect against E. coli isolated from companion rabbits was evaluated.. Five E. coli strains from clinically healthy pet rabbits were isolated and identified using VITEK2 system. Minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) values were detected with microdilution method according to CLSI guidelines. One isolate with highest MIC value detected in serum was selected for bacterial killing rate determination. Time-kill curves were determined as described by Lee et al (2017). Antimicrobial activity was determined in rabbit serum with addition of LVFX in concentrations of 0.5 MIC-32 MIC (in vitro) and in serum samples from rabbits treated with LVFX 5 mg/kg IM and SC administration (ex vivo).. Highest E. coli MIC was 0.03 µg/mL, highest MBC value was 0.25 µg/mL. After initial bacterial inhibition, 0.5 and 1 MIC concentrations of LVFX resulted in growth of E. coli after 24 hours of incubation (lower than control sample). 2MIC – 32MIC concentrations of LVFX, resulted in bacterial eradication after 24 hours of incubation. All serums samples from rabbits treated with 5 mg/kg LVFX parenterally from 0.5, 1, 2, 4, 8 and 10 h post administration were able to eradicate sensitive E. coli strain within 24 hours of incubation. AUC0-24/MIC, a PK/PD efficacy index for fluoroquinolones (>72 represents efficacy, according to Madsen et al., 2019) was calculated to be 302 and 310 h for IM and SC routes of administration respectively. . According to rates of bacterial killing in vitro and ex vivo, levofloxacin may be an effective treatment for E. coli infection eradication for sensitive strains with MIC values of 0.03 µg/mL and lower.
Period29 Mar 2023
Event titleRSU International Research Conference 2023: Knowledge for Use in Practice
Event typeConference
OrganiserRīga Stradiņš University
LocationRiga, LatviaShow on map
Degree of RecognitionInternational

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