In Vitro Fluoroquinolone Resistance in Staphylococcal Endophthalmitis Isolates

Darlene Miller
2006 Archives of Ophthalmology  
Objective: To evaluate the in vitro susceptibility and crossresistance of gatifloxacin and moxifloxacin vs older fluoroquinolones among coagulase-negative staphylococci recovered from patients with clinical endophthalmitis. Methods: A combination of E tests and disk diffusion methods was used to determine in vitro susceptibility and cross-resistance for 111 coagulase-negative staphylococci isolates recovered during a 15-year period (January 1, 1990, to December 31, 2004) against 5
more » ... nst 5 fluoroquinolones. Results: In vitro susceptibilities (percentage sensitive) in descending order were as follows: gatifloxacin, 74.5%; moxifloxacin, 72.1%; levofloxacin, 69.3%; ciprofloxacin, 65.6%, and ofloxacin, 60.4%. More than 65% of the coagulase-negative staphylococci resistant to ciprofloxacin (n = 38) demonstrated in vitro cross-resistance to gatifloxacin (25 [65.8%] of 38) and moxifloxacin (27 [71.1%] of 38). During the initial 5 years (January 1, 1990, to December 31, 1994, 96.6% of the coagulase-negative staphylococci were sensitive to gatifloxacin and moxifloxacin, with minimal inhibitory concentration required to inhibit or kill 90% of the isolates of 0.19 µg/mL and 0.12 µg/mL, respectively. During the last 5-year period (January 1, 2000, to December 31, 2004, the percentage of sensitive coagulase-negative staphylococci declined to 65.4% for gatifloxacin and moxifloxacin (P=.02). Minimal inhibitory concentration required to inhibit or kill 90% of the isolates was 32 µg/mL or greater for both drugs.
doi:10.1001/archopht.124.4.479 pmid:16606872 fatcat:df3pjvhr5vcpxjexgn7ikojo3e