Two Different Concentrations of Topical Levofloxacin for the Treatment of Multidrug-Resistant Pseudomonas aeruginosa Keratitis.
OBJECTIVE
To compare the efficacy of topical 1.5% and 0.5% levofloxacin (LVFX) for the treatment of multidrug-resistant Pseudomonas aeruginosa (MDRP) keratitis in rabbits.


METHODS
In a rabbit eye, we produced an MDRP keratitis model by excising a 2-mm circular disc of the cornea up to a depth of one-half of the stromal layer and inoculated an MDRP strain into the corneal concavity. Nine hours after inoculation and after confirming that MDRP keratitis had developed, we treated the eyes topically with 0.5% levofloxacin, 1.5% levofloxacin, or phosphate-buffered saline (PBS) every 6 h until 57 h postinfection. The infected eyes were evaluated by clinical score, histopathological examination, and viable bacterial count (colony forming units).


RESULTS
In the MDRP keratitis model, clinical score was significantly lower in 0.5% and 1.5% levofloxacin-treated groups than in PBS-treated group and was the lowest in 1.5% levofloxacin-treated group. Histopathological examination showed maintenance of corneal translucency and little influx of polymorphonuclear neutrophils in 1.5% levofloxacin-treated group. Viable bacterial count in the infected cornea was significantly lower in 0.5% levofloxacin-treated group compared with PBS-treated group, while no viable bacteria were detected in 1.5% levofloxacin-treated group.


CONCLUSIONS
Using our MDRP keratitis model, we showed that topical 0.5% levofloxacin is not adequately effective, while 1.5% levofloxacin is efficacious in controlling MDRP keratitis.
1 Department of Ophthalmology, Tokyo Medical University , Tokyo, Japan .|2 Department of Surgery, Keio University , Tokyo, Japan .
Kazuki
K
Tajima
1 Department of Ophthalmology, Tokyo Medical University , Tokyo, Japan .
Taku
T
Miyake
3 Department of Microbiology, Tokyo Medical University , Tokyo, Japan .
Naohito
N
Koike
1 Department of Ophthalmology, Tokyo Medical University , Tokyo, Japan .
Takaaki
T
Hattori
1 Department of Ophthalmology, Tokyo Medical University , Tokyo, Japan .
Hiroki
H
Takahashi
3 Department of Microbiology, Tokyo Medical University , Tokyo, Japan .
Tetsuya
T
Matsumoto
4 Department of Molecular Pathology, Tokyo Medical University , Tokyo, Japan .
Koji
K
Fujita
4 Department of Molecular Pathology, Tokyo Medical University , Tokyo, Japan .
Masahiko
M
Kuroda
1 Department of Ophthalmology, Tokyo Medical University , Tokyo, Japan .|5 University Veterinary Medical Center, Tottori University , Tottori, Japan .
Norihiko
N
Ito
1 Department of Ophthalmology, Tokyo Medical University , Tokyo, Japan .
Hiroshi
H
Goto
D060433:Administration, Ophthalmic; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D015169:Colony Count, Microbial; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D024901:Drug Resistance, Multiple, Bacterial; D015818:Eye Infections, Bacterial / Q000188:drug therapy / Q000382:microbiology; D007634:Keratitis / Q000188:drug therapy* / Q000382:microbiology; D064704:Levofloxacin / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D011552:Pseudomonas Infections / Q000188:drug therapy* / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D011817:Rabbits
D000900:Anti-Bacterial Agents; D064704:Levofloxacin