Purchase this article with an account.
C. L. Balzli, C. C. McCormick, A. R. Caballero, A. Tang, R. J. O'Callaghan; Lysostaphin Activity wWthin the Aqueous Humor. Invest. Ophthalmol. Vis. Sci. 2007;48(13):3925.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
To test the hypothesis that lysostaphin, a bactericidal enzyme, can remain active within the rabbit anterior chamber far longer than a fluoroquinolone antibiotic.
Lysostaphin (20 lytic units, 250 µg), gatifloxacin (300 µg), or Tris-buffered saline (TBS; 40 mM Tris, pH 7.4) were injected into the rabbit anterior chamber and at 12, 24, 48, 72, and 96 hours aqueous humor was collected. The aqueous (50 µl) was assayed for lysostaphin or gatifloxacin bactericidal activity by measurements of Staphylococcus aureus killing (10,000 colony forming units [CFU] of log phase bacteria incubated at 33oC for 1 hour); each sample was subsequently serially diluted and plated in triplicate onto tryptic soy agar to determine the number of surviving bacteria.
Bactericidal assays of aqueous humor from lysostaphin injected eyes demonstrated > 95 % killing of S. aureus through 72 hours and 28 % killing at 96 hours post injection. In contrast, gatifloxacin bactericidal activity in aqueous humor accounted for < 25 % killing at 12 hours and < 5 % at 48 hours. Aqueous injected with TBS demonstrated < 10 % killing of S. aureus at both 12 and 24 hours.
Following injection of lysostaphin into the aqueous humor, the bactericidal activity lasted for at least 96 hours, a period far longer than the commonly employed antibiotic gatifloxacin. These findings have possible implications for prophylaxis for Staphylococcal endophthalmitis.
This PDF is available to Subscribers Only