Effectiveness of fluoroquinolones against Mycobacterium abscessus in vivo.
OBJECTIVE
To determine the effectiveness of fluoroquinolones against Mycobacterium abscessus in vivo.


METHODS
M. abscessus growth was determined quantitatively in rabbit corneas after intrastromal bacterial injection (10(4) CFU/cornea; n >or= 4 corneas per group). Eyes were treated topically with 0.3% ciprofloxacin, 0.5% levofloxacin, or 0.5% moxifloxacin by three protocols: (1) 1 drop of antibiotic applied hourly for 10 hr on day 3 postinfection (PI); (2) 1 drop applied every 2 hr for 10 hr on days 2 and 3 PI; or (3) 1 drop applied every 2 hr for 10 hr on days 1, 2, and 3 PI. Corneas were cultured 1 hr after the last topical drop. Results are expressed as the log CFU.


RESULTS
Bacteria in control group reached maximal numbers in vivo by day 3 PI (approximately 6 logs CFU/cornea). Treatment of infected eyes on day 3 with moxifloxacin or levofloxacin resulted in approximately 2.0 log decrease in CFU/cornea relative to the untreated control. Treatment on days 2 and 3 with moxifloxacin or levofloxacin resulted in approximately 3.0 and 2.5 log CFU/cornea decrease, respectively. Ciprofloxacin had no effect on bacterial load. Treatment on days 1, 2, and 3 with moxifloxacin resulted in a 5.5 log CFU decrease, whereas treatment with levofloxacin or ciprofloxacin resulted in a approximately 4.0 log CFU decrease.


CONCLUSIONS
Moxifloxacin, and to a lesser extent levofloxacin and ciprofloxacin, demonstrated significant effectiveness for reducing the number of M. abscessus in vivo, suggesting the potential usage of these agents in prevention of M. abscessus keratitis.
Caballero
Armando R
AR
Department of Microbiology, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA.
Marquart
M E
ME
O'Callaghan
Richard J
RJ
Thibodeaux
B A
BA
Johnston
K H
KH
Dajcs
J J
JJ
D000287:Administration, Topical; D000818:Animals; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001372:Aza Compounds / Q000008:administration & dosage / Q000627:therapeutic use; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000627:therapeutic use; D015169:Colony Count, Microbial; D003319:Corneal Stroma / Q000382:microbiology; D003320:Corneal Ulcer / Q000188:drug therapy* / Q000382:microbiology; D004195:Disease Models, Animal; D015818:Eye Infections, Bacterial / Q000188:drug therapy* / Q000382:microbiology; D024841:Fluoroquinolones / Q000008:administration & dosage / Q000627:therapeutic use*; D064704:Levofloxacin; D008826:Microbial Sensitivity Tests; D000077266:Moxifloxacin; D009165:Mycobacterium Infections, Nontuberculous / Q000188:drug therapy* / Q000382:microbiology; D016926:Mycobacterium chelonae / Q000302:isolation & purification*; D015242:Ofloxacin / Q000008:administration & dosage / Q000627:therapeutic use; D009883:Ophthalmic Solutions / Q000008:administration & dosage / Q000627:therapeutic use; D011804:Quinolines / Q000008:administration & dosage / Q000627:therapeutic use; D011817:Rabbits
D000900:Anti-Bacterial Agents; D001372:Aza Compounds; D024841:Fluoroquinolones; D009883:Ophthalmic Solutions; D011804:Quinolines; D002939:Ciprofloxacin; D064704:Levofloxacin; D015242:Ofloxacin; D000077266:Moxifloxacin