Characterization of baseline polybacterial versus monobacterial infections in three randomized controlled bacterial conjunctivitis trials and microbial outcomes with besifloxacin ophthalmic suspension 0.6.

BACKGROUND/PURPOSE: To date, studies examining polymicrobial infections in ocular disease have mostly been limited to keratitis or endophthalmitis. We characterized polybacterial infections compared to monobacterial infections in prior clinical studies evaluating besifloxacin ophthalmic suspension 0.6% for the treatment of bacterial conjunctivitis and report on associated microbiological outcomes. METHODS: In this post-hoc analysis, microbiological data for subjects with conjunctivitis due to one or more than one bacterial species in three previous studies (two vehicle-, one active-controlled) of besifloxacin were extracted. Bacterial species identified at baseline were deemed causative if their colony count equaled or exceeded species-specific prespecified threshold criteria. In subjects with polybacterial infections, the fold-increase over threshold was used to rank order the contribution of individual species. Baseline pathogens and their minimum inhibitory concentrations (MICs) for common ophthalmic antibiotics were compared by infection type, as were microbial eradication rates following treatment with besifloxacin. RESULTS: Of 1041 subjects with culture-confirmed conjunctivitis, 17% had polybacterial and 83% had monobacterial conjunctivitis at baseline. In polybacterial compared to monobacterial infections, Haemophilus influenzae and Streptococcus pneumoniae were identified less frequently as the dominant infecting species (P = 0.042 and P<0.001, respectively), whereas Streptococcus mitis/S. mitis group was identified more frequently as dominant (P<0.001). Viral coinfection was also identified more frequently in polybacterial infections (P<0.001). Staphylococcus aureus was the most common coinfecting species in polybacterial infections and the second most common dominant species in such infections. With few exceptions, MICs for individual species were comparable regardless of infection type. Clinical microbial eradication rates with besifloxacin were high regardless of infection type (P≤0.016 vs vehicle at follow-up visits). CONCLUSIONS: Approximately one in five subjects with bacterial conjunctivitis are infected with more than one bacterial species underscoring the need for a broad-spectrum antibiotic for such infections. Besifloxacin treatment resulted in robust eradication rates of these infections comparable to monobacterial infections. TRIAL REGISTRATION: NCT000622908, NCT00347932, NCT00348348.

Antibiotic resistance among bacterial conjunctival pathogens collected in the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study.

The Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) surveillance study evaluates in vitro antibiotic resistance among Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae isolates from ocular infections. Here we report resistance rates and trends among conjunctival-sourced ocular isolates collected across the US from 2009 through 2016. A total of 1198 conjunctival isolates (483 S. aureus, 305 CoNS, 208 H. influenzae, 118 S. pneumoniae, and 84 P. aeruginosa) were collected from patients with presumed bacterial conjunctivitis from 57 sites across 40 states. A large proportion of staphylococci demonstrated resistance to oxacillin and azithromycin, while resistance was low against the majority of antibiotics tested for S. pneumoniae, P. aeruginosa, and H. influenzae. Multidrug resistance (≥3 antibiotic classes) was found in 30.2% of S. aureus and 39.0% of CoNS isolates, and methicillin resistance more than doubled the rate of multi-drug resistance (methicillin-resistant S. aureus [MRSA], 76.5%; methicillin-resistant CoNS isolates, 72.8%). There was a pattern of increasing mean percent resistance with increasing age by decade of life among S. aureus, MRSA, and CoNS (P≤0.038). Over the eight-year study period, there were small yet significant decreases in resistance rates among S. aureus to azithromycin, ciprofloxacin, tobramycin, trimethoprim, and oxacillin (P≤0.003), and among CoNS and P. aeruginosa (both P<0.05) to ciprofloxacin. These data indicate that antibiotic resistance is high, but did not increase, among conjunctival-sourced isolates collected in the US from 2009 through 2016. For certain antibiotic/pathogen combinations, there was a trend of decreased resistance, including a decrease in oxacillin resistance among S. aureus.

Besifloxacin Ophthalmic Suspension 0.6% Compared with Gatifloxacin Ophthalmic Solution 0.3% for the Treatment of Bacterial Conjunctivitis in Neonates.

PURPOSE: The aim of this study was to evaluate the safety and efficacy of topical besifloxacin ophthalmic suspension 0.6% compared with gatifloxacin ophthalmic solution 0.3% in the treatment of bacterial conjunctivitis in neonates. METHODS: This was a multicenter, randomized, double-masked, parallel group study. Subjects ≤31 days of age with severity grade ≥1 (scale 0-3) for both conjunctival discharge and conjunctival hyperemia were randomized to besifloxacin or gatifloxacin instilled three times daily for 7 days, and completed five study visits (three clinic visits and two phone calls). Primary endpoints included clinical resolution (absence of both conjunctival discharge and conjunctival hyperemia) at visit 5 (day 8 or 9) and ocular and non-ocular treatment-emergent adverse events (AEs). Bacterial eradication was a secondary endpoint. RESULTS: Thirty-three subjects were included in the intent-to-treat (ITT) population. All were aged <28 days, with a mean (standard deviation) age of 15.5 days (6.0), and 57.6% were female. Twenty-two subjects had culture-confirmed conjunctivitis in at least one eye (modified ITT [mITT] population), most often with Gram-positive bacteria. Visit 5 clinical resolution and bacterial eradication rates were comparable among besifloxacin- and gatifloxacin-treated study eyes (clinical resolution: 12/16 [75.0%] vs. 12/17 [70.6%] for the ITT population, and 11/13 [84.6%] vs. 7/9 [77.8%] for the mITT population; bacterial eradication: 12/13 [92.3%] vs. 8/9 [88.9%] for the mITT population, respectively). No AEs were reported in the besifloxacin treatment group, and AEs reported in the gatifloxacin group were considered not treatment-related. CONCLUSIONS: In this small study in neonates, both besifloxacin and gatifloxacin appeared effective and safe in the treatment of bacterial conjunctivitis. Larger studies are warranted.