Abstract
Purpose: :
We compared the antibacterial efficacy of AzaSite (1.0% azithromycin formulated in DuraSite containing 0.01% benzalkonium chloride) to Azyter (1.5% azithromycin formulated in a non-preserved oil) using in vitro time-kill studies..
Methods: :
Time-kill studies were processed to test Proteus mirabilis, Staphylococcus epidermidis, S aureus, S aureus [MRSA] azithromycin-resistant, Streptocoocus viridans, St pneumoniae, Pseudomonas aeruginosa, P putida, Branhamella catarrhalis, Bacillus cereus, Enterococcus faecalis, Serratia marcescens, Enterobacter aerogenes, Klebsiella pneumoniae, E coli, and Haemophilus influenzae to AzaSite and Azyter at time points 0, 15 min, 30 min, 1 hr, 2 hrs, 4 hrs, 6 hrs, 8 hrs, and 24 hrs, using the standard colony count method.
Results: :
AzaSite (94%, 15/16) significantly (p=0.00017, Fisher’s exact test) killed more bacterial isolates by 15 min than Azyter (25%, 4/16). The colony counts for Proteus mirabilis at each time point (15 min to 8 hrs) were more reduced for AzaSite than Azyter.
Conclusions: :
In vitro time-kill studies demonstrated that AzaSite was more effective in eradicating bacterial isolates than Azyter. Clinical trials are recommended to determine if these in vitro results parallel in vivo efficacy.
Keywords: antibiotics/antifungals/antiparasitics • clinical laboratory testing • bacterial disease