VIGAMOX^® Solution Has a Rapid Speed of Bacterial Kill In Vitro

VIGAMOX^® solution eradicates 99.9% of Haemophilus influenzae¹ and Streptococcus pneumoniae^1,2 in vitro in as little as one hour*^†

Rapid eradication of bacteria is a critical component in the management of bacterial conjunctivitis due to the inevitable decrease in the spread of pathogens and faster resolution of clinical symptoms. Speed of bacterial kill studies are designed to evaluate the effects of antibiotics on bacterial counts in ophthalmic products. These studies are designed to mimic clinical concentrations of antibiotics through dilutions that correspond to expected tear levels in the eye at various timepoints.¹ Data from speed of bacterial kill studies can provide important insight into the efficacy of bacteriocidal agents and their ability to quickly eradicate pathogens.

The effect of VIGAMOX^® solution on 2 common ocular pathogens was tested in speed of bacterial kill studies including; H. influenzae and S. pneumoniae. Bacteriocidal kill was defined as a 99.9% reduction in colony forming units (CFU’s). Bacterial isolates were obtained from patients with bacterial conjunctivitis and were exposed to VIGAMOX^® solution. Bacteria were washed, filtered, and incubated to determine the number of surviving bacteria.

Results

VIGAMOX^® solution destroyed 99.9% of S. pneumoniae in approximately 2 hours and H. influenzae within 30 minutes.¹ In fact, other studies have shown that S. pneumoniae bacteria exposed to VIGAMOX^® solution began to die within 15 minutes.³ Other studies have demonstrated a 99.9% eradication of S. pneumoniae in as little as an hour.²

Photographs of surviving bacterial colonies were taken at 15, 30, and 60 minutes after exposure to VIGAMOX^® solution or control (see figure below).²

Conclusions

These data provide strong evidence for a rapid reduction of bacterial colony counts by VIGAMOX^® solution against conjunctival pathogens S. pneumoniae and H. influenzae. 

*Patients should be advised to use the full course of therapy — 7 days.
^†In vitro data are not always indicative of clinical success or microbiological eradication in a clinical setting. Clinical significance unknown.

References

1. Lichtenstein SJ, Wager RS, Jamison T, Bell B, Stroman DW.  Speed of bacterial kill with a fluoroquinolone compared with nonfluoroquinolones: Clinical implications and a review of kinetics of kill studies. Adv Ther. 2007;24(5):1098-1111.
2. Lichtenstein SJ, Dorfman M, Kennedy R, Stroman D. Controlling contagious bacterial conjunctivitis. J Pediatr Ophthalmol & Strabismus. 2006;43(1):19-26.
3. VIGAMOX® solution destroyed 99.9% of S. pneumoniae in approximately 2 hours and H. influenzae within 30 minutes.¹ In fact, other studies have shown that S. pneumoniae bacteria exposed to VIGAMOX® solution began to die within 15 minutes.³