TYLOSIN

Pivotal Study:

In vitro microbiological study (Pridmore, 2006a): MICs for tylosin were determined in 100 bacterial strains isolated from faeces of healthy volunteers who had not received antibiotic therapy during the 3 months prior to faecal collection and who had experienced no symptoms of diarrhoea within 4 weeks of sample collection. Ten species were isolated, and 10 strains/species were used in the MIC tests. For each strain, the inoculum was enumerated to demonstrate compliance with Clinical and Laboratory Standards Institute (CLSI) guidelines. Antibacterial activity was demonstrated among the strains from other species; the most susceptible were the Gram-positive anaerobes, Bifidobacterium, Clostridium, Eubacterium and Peptostreptococcus. The Committee calculated an estimated NOAEC (MICcalc) for colonization barrier disruption using 90% confidence limit mean MIC50 values for the most relevant and sensitive genera as follows: Lower 90% CL = Mean MIC50 – Std Dev/(vn × t0.10,df), where: Mean MIC50 = mean log transformed MIC50s; Std Dev = standard deviation log-transformed MIC50s; n = number of MIC50s; and t0.10,df = 90th percentile from central t-distribution with degrees of freedom (df) = n-1. The MIC90s for Bacteroides, Bifidobacterium spp., Clostridium spp., Enterococcus spp., Eubacterium spp.,Fusobacterium spp., Lactobacillus spp. and Peptostreptococcus were used to obtain the following values: • MIC90 = 5.44 µg/ml • t = 1.397 • Lower 90% CL = 3.76 • MICcalc = 1.698 µg/ml

Animal Specie:

Human gut flora

Effect:

Growth inhibition

Point of departure:

1.698 µg/ml (MICcalc)