Abstract
Abstract: :
Purpose: The 4th generation fluoroquinolones are broad–spectrum antibiotics approved to treat conjunctivitis due to susceptible organisms. Off label use for other ocular complaints maybe more frequent. This study attempts to document the frequency, clinical diagnosis, pathogen selection and emerging resistance among patients presenting on 4th generation fluoroquinolones. Methods: Culture results for 1,471 patients presenting at our Institute between January 2003 and October 2004, were reviewed and data on those pretreated with Moxifloxacin and or Gatifloxacin was compiled and analyzed for presenting diagnosis, culture positive rates, pathogen frequency and emerging resistance. Results: Thirty (30%) percent or 176 of the 583 (39.6%) patients on antibiotics presented on Moxifloxacin (58%) and or Gatifloxacin (42%). Presenting diagnosis for this group of patients included keratitis (83%), soft tissue and intraocular infections (10%) and conjunctivitis (7%). The culture positive rate (37.5%) for the 4th generation antibiotics was significantly lower than for patients on nonfluroquinolones antibiotics (53.2%, p=0.00) or no antibiotics (47.6%, p=0.015). There were no significant differences between the culture positive rates for Moxifloxacin (39.8%) vs Gatifloxacin (34.2%) or older fluoroquinolones (37.6%). Patients presenting on the 4th generation fluoroquinolones were significantly more likely to be culture positive (54.5%) for fungi, acanthamoeba, mycobacteria and or nocardia vs patients presenting on nonfluoroquinolones antibiotics (22.4%, p=0.00) or no antibiotics (10.7%, p =0.00). General in vitro susceptibility for both Gatifloxacin and Moxifloxacin was 88%. There was a significance difference between coverage for gram positive (76%) vs gram negative (98%, p=0.00, ) isolates. Other than S. aureus and M. chelonae/abscess, emerging resistance among these ocular isolates was documented for P. aeruginosa (3), Streptococci species (2) and other gram negative rods (3). Conclusions: Ninety–three (93) percent of patients presenting on 4th generation fluoroquinolones were treated for ocular complaints other than conjunctivitis. Nonbacterial pathogens and mycobacteria were more frequently associated with patients pretreated with 4th generation fluoroquinolones. Emerging resistance was documented for common ocular isolates of streptococci and P. aeruginosa.
Keywords: drug toxicity/drug effects • antibiotics/antifungals/antiparasitics • bacterial disease