Influence of fluoroquinolone susceptibility on the therapeutic response of fluoroquinolone-treated bacterial keratitis.
OBJECTIVE
To estimate how a corneal isolate's minimal inhibitory concentration for a fluoroquinolone agent affects the rate of clinical response of bacterial keratitis to fluoroquinolone therapy.


METHODS
Prospective cohort study.


METHODS
Six hundred sixty-three individuals with suspected bacterial keratitis underwent diagnostic corneal scraping and were treated with topical 0.3% ciprofloxacin solution or ointment. Of 407 patients with culture-confirmed bacterial keratitis, improvement and cure rates with ciprofloxacin monotherapy were estimated for 391 who had in vitro ciprofloxacin susceptibility of the principal corneal isolate.


METHODS
Slitlamp biomicroscopic assessment for clinical improvement of corneal inflammation and for clinical cure with complete reepithelialization.


RESULTS
Adjusted rates of improvement and of cure were reduced, respectively, by 43% (95% confidence limits, 8%, 64%) and by 29% (95% confidence limits, 0%, 49%) among corneal infections having a ciprofloxacin minimal inhibitory concentration above 1.0 micro g/mL compared with those with more sensitive isolates.


CONCLUSIONS
Corneal infection by relatively ciprofloxacin-resistant bacteria responds more slowly to ciprofloxacin therapy. Antibacterial susceptibility testing of corneal cultures may predict the fluoroquinolone therapeutic response rate of bacterial keratitis.
Wilhelmus
Kirk R
KR
Sid W. Richardson Ocular Microbiology Laboratory, Cullen Eye Institute, Baylor College of Medicine, Houston, TX 77030, USA. kirkw@bcm.tmc.edu
Abshire
Robert L
RL
Schlech
Barry A
BA
D000890:Anti-Infective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D001419:Bacteria / Q000187:drug effects* / Q000302:isolation & purification; D002939:Ciprofloxacin / Q000494:pharmacology / Q000627:therapeutic use*; D003315:Cornea / Q000382:microbiology; D003320:Corneal Ulcer / Q000188:drug therapy* / Q000382:microbiology; D024881:Drug Resistance, Bacterial; D015818:Eye Infections, Bacterial / Q000188:drug therapy* / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009824:Ointments; D009883:Ophthalmic Solutions; D011446:Prospective Studies
D000890:Anti-Infective Agents; D009824:Ointments; D009883:Ophthalmic Solutions; D002939:Ciprofloxacin