Enterococcus faecalis Isolates Clinically Isolated from Urinary Tract

25 26 We examined E. faecalis strains clinically isolated from 100 UTI patients for their 27 susceptibility to levofloxacin (LVX) by measuring the minimal inhibitory concentration 28 (MIC), and investigated amino acid mutations by direct DNA sequencing which was 29 then correlated with LVX resistance. Next we studied risk factors for LVX resistance 30 such as age, sex, and previous fluoroquinolone use, and investigated the statistical 31 correlation of these risk factors with each amino acid mutation and levofloxacin (LVX) 32 resistance. Of the 100 isolates tested, 14 isolates showed LVX resistance and all of 33 these isolates had amino acid mutations. We demonstrated that 2 out of 4 mutations 34 (Ser83-to-Ile in gyrA and Ser80-to-Ile in parC) had a significant correlation to LVX 35 resistance. There was a significant relationship between isolates with 2 or 3 amino acid 36 mutations and LVX resistance. In addition, we found a significant correlation between 37 the previous use of fluoroquinolones and LVX resistance or the presence of mutations 38 and also demonstrated that the previous use of other types of antibiotics was 39 significantly related to the presence of mutations by multivariate analysis. In conclusion, 40 we found significant correlation between amino acid mutations in E. faecalis, LVX 41 resistance and risk factors such as previous use of fluoroquinolone. 42 43 44