Topical ophthalmic moxifloxacin elicits minimal or no selection of fluoroquinolone resistance among bacteria isolated from the skin, nose, and throat.

PURPOSE: To investigate whether moxifloxacin therapy of bacterial conjunctivitis in children changes the moxifloxacin susceptibility of bacterial isolates in eyes, cheeks below eyes, nares, and throat. METHODS: Patients (age: 1 to 12 years, n = 105) with bacterial conjunctivitis were treated topically with moxifloxacin three times a day for 7 days. Gender- and age-matched subjects with normal eyes (age: 1 to 12 years, n = 57) served as the control group. Microbiological specimens were collected on days 1 (prior to therapy), 8 (1 day after end of therapy), and 42 (follow-up). Specimens were processed to recover total bacteria and bacteria that grew on fluoroquinolone-selective media. Bacteria were identified to the species level and susceptibility to moxifloxacin and selected other antibiotics determined. RESULTS: The primary pathogens recovered from the infected eyes on day 1 before therapy were Haemophilus influenzae, Streptococcus pneumoniae, and Staphylococcus aureus. None of the pre-therapy isolates of H. influenzae and S. pneumoniae were resistant to moxifloxacin. Isolates of these two pathogenic species were also recovered primarily from the nose and eyes. Moxifloxacin-resistant S. aureus isolates (minimum inhibitory concentration 1.0 µg/mL or greater) were recovered from the nose and throat prior to topical dosing on day 1. However, there was no change in the frequency of moxifloxacin-resistant isolates of S. aureus following treatment with moxifloxacin. CONCLUSION: Treatment of conjunctivitis with topical ophthalmic moxifloxacin did not select for moxifloxacin resistance in H. influenzae, S. pneumoniae, or S. aureus in the eye or distal body sites.

Microbiological efficacy of a new ophthalmic formulation of moxifloxacin dosed twice-daily for bacterial conjunctivitis.

INTRODUCTION: An alternative formulation of 0.5% moxifloxacin ophthalmic solution (Moxeza, MOXI-AF, Alcon Laboratories, Inc., Fort Worth, TX, USA) containing xanthan gum to prolong retention on the eye has been developed. MOXI-AF was designed to optimize the treatment regimen for bacterial conjunctivitis for the convenience of the patient with twice-daily dosing. METHODS: A safety and efficacy clinical study was conducted as a multicenter, vehiclecontrolled, randomized, double-masked, parallel group study in clinically diagnosed bacterial conjunctivitis patients aged >28 days. MOXI-AF or its vehicle was dosed one drop twice-daily for 3 days. Microbiological specimens were obtained from affected eyes on day 1, prior to the initial dose, and on day 4 after 3 days of dosing, and processed using routine clinical microbiology laboratory methods. All recovered bacteria were identified to the species level. RESULTS: This paper reports on the microbiological success rate, a secondary efficacy variable in the trial. All patients (1180) were randomized to treatment. Patient age ranged from 30 days to 92 years. The microbiological success rate for patients treated topically with MOXI-AF twice-daily for 3 days was 74.5%, compared with 56.0% of patients treated with its vehicle control (P<0.0001). MOXI-AF was also statistically more effective than vehicle in eradicating the three principle conjunctivitis pathogens, Haemophilus influenzae (98.5% vs. 59.6%, respectively), Streptococcus pneumoniae (86.4% vs. 50.0%, respectively), and Staphylococcus aureus (94.1% vs. 80.0%, respectively) (P<0.001). CONCLUSION: The xanthan gum-based 0.5% moxifloxacin ophthalmic formulation, MOXI-AF, provides effective eradication of the three principle causative pathogens of bacterial conjunctivitis across all age groups when dosed twice-daily for 3 days.

In vitro and in vivo potency of moxifloxacin and moxifloxacin ophthalmic solution 0.5%, a new topical fluoroquinolone.

Fluoroquinolones are a class of synthetic antibacterial agents that were approved for ocular therapy in 1991 and have become popular therapy for the treatment and prevention of various ocular infections. These agents are synthetic, broad-spectrum, rapidly bactericidal, and have good penetration into ocular tissues. Their main mechanism of action is the inhibition of bacterial enzymes needed for bacterial DNA synthesis. However, antibiotic resistance occurred swiftly to the earlier fluoroquinolones and better fluoroquinolones were needed. The fourth-generation fluoroquinolones, such as moxifloxacin and gatifloxacin, have enhanced activity against gram-positive bacteria while retaining potent activity against most gram-negative bacteria. These fourth-generation fluoroquinolones have improved penetration into the anterior chamber and have also demonstrated increased in vivo efficacy in several animal models of ocular infections. In addition, topical ophthalmic antibiotic products can deliver antibiotic concentrations directly to the eye that are thousands of times higher than their MICs. This article reviews published data describing the in vitro potency of moxifloxacin and its in vivo activity for treating and preventing experimental ocular infections.