Comparative in vitro resistance of the new fluoroquinolones among aerobic Gram-negative bacilli-resistant to amikacin in a hospital setting: a 3-year study
Abstract number: 902_p1709
To assess the rate of resistance to fluoroquinolones in aerobic Gram-negative bacilli (GNB) that is resistant to amikacin and to determine if the fluoroquinolone resistance has increased overtime with the use of this new medications.
From January 2000 to December 2002 aerobic GNB isolates resistant to amikacin at the San Juan VAMC were prospectively collected and tested for suceptibility to three fluoroquinolones (levofloxacin, gatifloxacin and moxifloxacin). Percentage of resistance was calculated per year of study and changes in resistance overtime were evaluated with Chi-Square test.
Fluoroquinolones resistance was analysed for the following bacterias: P. aeruginosa, E. coli, Klebsiella, Enterobacter, Citrobacter, Serratia, P. mirabillis, Morganella and Proteus. E. coli overall resistance was significantly higher to moxifloxacin (55.9%), gatifloxacin (55.9%) and levofloxacin (52.3%). P. mirabilis was more susceptible to levofloxacin (16.8%resistance) than to the other quinolones (gatifloxacin 21.4%, moxifloxacin 26.9%). P. aeruginosa showed a very high resistance to levofloxacin (69.5%), moxifloxacin (77.5%) and gatifloxacin (72.9%). Isolates of Klebsiella sp. had lower resistance to levofloxacin (19.4%) and gatifloxacin (18.8%) than to moxifloxacin with resistance of 29.6%. Serratia isolates were significantly more susceptible to levofloxacin with only 7.0% resistance. The other quinolones showed higher resistance to Serratia with gatifloxacin (15.0%)and moxifloxacin (20.7%). E. coli and P. mirabilis showed a statistically significant increase in resistance overtime to all three fluoroquinolones. Resistance to Citrobacter, Enterobacter, Morganella and Providencia remained unchanged through years on study.
The resistance to amikacin among GNB in our hospital setting has required the use of alternative drugs. The new quinolones have been used as an alternative in patients with resistance to aminoglycosides but also emergence and evolution of quinolones resistance has affected their use over the years. In our study this was noticed especially on E. coli and P. mirabilis with a significant increase in resistance overtime. Some species including E. coli, P. aeruginosa, and Providencia showed high resistance (>50%) to the three quinolones tested. Species like Serratia, Klebsiella and Proteus had lower resistance so in this species the use of quinolones could be a useful alternative."
|Session name:||XXIst ISTH Congress|
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