Antibiotic resistance of bacterial pathogens isolated from the conjunctiva in the Antibiotic Resistance Monitoring in Ocular micRoorganisms (ARMOR) surveillance study (2009-2021).

Antibiotic resistance in bacterial ocular infections is of significant clinical concern and may affect treatment outcomes. We report on in vitro antibiotic susceptibility rates and trends among conjunctival-sourced isolates collected in the Antibiotic Resistance Monitoring in Ocular micRoorganisms (ARMOR) surveillance study. A total of 2214 conjunctival isolates (918 Staphylococcus aureus, 589 coagulase-negative staphylococci [CoNS], 194 Streptococcus pneumoniae, 171 Pseudomonas aeruginosa, and 342 Haemophilus influenzae) obtained between 2009-2021 were analyzed. Staphylococci were commonly resistant to azithromycin (≥54.8%) and oxacillin (≥29.3%). Resistance among S. pneumoniae isolates was notable for azithromycin (34.0%) and penicillin (28.9%), while P. aeruginosa and H. influenzae isolates were highly susceptible to most tested antibiotics. Methicillin-resistant staphylococci demonstrated greater concurrent resistance to other antibiotics than methicillin-susceptible isolates and exhibited high rates of multidrug resistance (≥74.0%). Among staphylococci, antibiotic resistance increased with patient age, and there were small decreases in resistance to several drugs over the 13-year period. These findings indicate that resistance to antibiotics routinely used in ophthalmic practice remains high among conjunctival isolates.

Characterization of Polybacterial versus Monobacterial Conjunctivitis Infections in Pediatric Subjects Across Multiple Studies and Microbiological Outcomes with Besifloxacin Ophthalmic Suspension 0.6.

INTRODUCTION: The choice of empiric therapy for bacterial conjunctivitis should be guided by an awareness of typical causative pathogen distributions. Bacterial conjunctivitis can be polybacterial, although pediatric-specific data are lacking. METHODS: This was a post-hoc analysis of data in pediatric subjects (1-17 years) from five bacterial conjunctivitis trials evaluating besifloxacin ophthalmic solution 0.6%. RESULTS: Of the 730 pediatric subjects with culture-confirmed conjunctivitis, nearly one-fourth (23.6%) had polybacterial infections and three-fourths (76.4%) had monobacterial infections at baseline. In both polybacterial and monobacterial infections, the most prevalent organisms were Haemophilus influenzae, Streptococcus pneumoniae, Staphylococcus aureus, and Streptococcus mitis/S. mitis group. In polybacterial versus monobacterial infections, S. mitis/S. mitis group (8.7% vs 4.3%; P=0.032) and Moraxella catarrhalis (4.7% vs 0.5%; P<0.001) were identified more frequently, whereas S. pneumoniae (14.0% vs 28.1%; P<0.001) was identified less frequently, as the dominant infecting species. MICs for individual species were similar for tested antibiotics regardless of polybacterial or monobacterial infection, except Staphylococcus epidermidis for which fluoroquinolone MICs were ≥3 dilutions higher for isolates of this species sourced from polybacterial compared to monobacterial infections. Treatment with besifloxacin resulted in microbial eradication in 79.1% of polybacterial and 92.3% of monobacterial infections (P≤0.005 vs vehicle). DISCUSSION: One in four pediatric bacterial conjunctivitis infections is polybacterial, highlighting the need for a broad-spectrum antibiotic when choosing empiric therapy.

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.

Trends in Antibiotic Resistance Among Ocular Microorganisms in the United States From 2009 to 2018.

Importance: Antibiotic resistance in ocular infections can affect treatment outcomes. Surveillance data on evolving antibacterial susceptibility patterns inform the treatment of such infections. Objective: To assess overall antibiotic resistance profiles and trends among bacterial isolates from ocular sources collected during 10 years. Design, Setting, and Participants: This cross-sectional study of longitudinal data from the ongoing, nationwide, prospective, laboratory-based surveillance study, the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) study, included clinically relevant isolates of Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Pseudomonas aeruginosa, and Haemophilus influenzae cultured from patients with ocular infections at US centers from January 1, 2009, to December 31, 2018. Main Outcomes and Measures: Minimum inhibitory concentrations were determined for various combinations of antibiotics and species. Odds ratios (ORs) were determined for concurrent antibiotic resistance; analysis of variance and χ2 tests were used to evaluate resistance rates by patient age and geographic region; Cochran-Armitage tests identified changing antibiotic susceptibility trends over time. Results: A total of 6091 isolates (2189 S aureus, 1765 CoNS, 590 S pneumoniae, 767 P aeruginosa, and 780 H influenzae) from 6091 patients were submitted by 88 sites. Overall, 765 S aureus (34.9%) and 871 CoNS (49.3%) isolates were methicillin resistant and more likely to be concurrently resistant to macrolides (azithromycin: S aureus: OR, 18.34 [95% CI, 13.64-24.67]; CoNS: OR, 4.59 [95% CI, 3.72-5.66]), fluoroquinolones (ciprofloxacin: S aureus: OR, 22.61 [95% CI, 17.96-28.47]; CoNS: OR, 9.73 [95% CI, 7.63-12.40]), and aminoglycosides (tobramycin: S aureus: OR, 18.29 [95% CI, 13.21-25.32]; CoNS: OR, 6.28 [95% CI, 4.61-8.56]) compared with methicillin-susceptible isolates (P < .001 for all). Multidrug resistance was observed among methicillin-resistant S aureus (577 [75.4%]) and CoNS (642 [73.7%]) isolates. Antibiotic resistance among S pneumoniae isolates was highest for azithromycin (214 [36.3%]), whereas P aeruginosa and H influenzae isolates showed low resistance overall. Differences in antibiotic resistance were found among isolates by patient age (S aureus: F = 28.07, P < .001; CoNS: F = 11.46, P < .001) and geographic region (S aureus: F = 8.03, P < .001; CoNS: F = 4.79, P = .003; S pneumoniae: F = 8.14, P < .001; P aeruginosa: F = 4.32, P = .005). Small changes in antibiotic resistance were noted over time (≤2.5% per year), with decreases in resistance to oxacillin/methicillin (oxacillin: -2.16%; 95% CI, -3.91% to -0.41%; P < .001) and other antibiotics among S aureus isolates, a decrease in ciprofloxacin resistance among CoNS (-1.38%; 95% CI, -2.24% to -0.52%; P < .001), and an increase in tobramycin resistance among CoNS (0.71%; 95% CI, -0.29% to 1.71%; P = .03). Besifloxacin retained consistently low minimum inhibitory concentrations. Conclusions and Relevance: Antibiotic resistance may be prevalent among staphylococcal isolates, particularly among older patients. In this study, a few small differences in antibiotic resistance were observed by geographic region or longitudinally.

An Evaluation of Staphylococci from Ocular Surface Infections Treated Empirically with Topical Besifloxacin: Antibiotic Resistance, Molecular Characteristics, and Clinical Outcomes.

INTRODUCTION: Understanding antibiotic resistance and toxin profiles among staphylococcal isolates in ocular infections can aid in therapeutic management and infection prevention strategies. We evaluated in vitro antibiotic resistance patterns and molecular traits of staphylococci isolated from patients with ocular surface infections. We also report on clinical outcomes for these patients following empirical treatment with topical besifloxacin ophthalmic suspension 0.6%. METHODS: This was a small observational study. Participating investigators from three clinical sites collected an initial ocular culture from the affected eye of patients presenting with ocular surface infections with presumed staphylococcal etiology. Clinical outcome data for patients with confirmed staphylococcal infections were collated later through retrospective review of patient medical records. Staphylococcal species identification in ocular cultures, in vitro antibiotic susceptibility testing, and PCR-based determination of methicillin resistance cassettes and toxin genotypes were conducted at a central laboratory. Isolates were categorized as susceptible or resistant based on systemic breakpoints, where available. RESULTS: Cultures were collected from 43 patients, and staphylococcal infections were confirmed in 25 patients. Two isolates of Staphylococcus aureus and 27 isolates of Staphylococcus epidermidis were identified. Both S. aureus isolates were methicillin-susceptible, lacked the gene encoding Panton-Valentine leukocidin, and carried few enterotoxin genes. Eight (30%) S. epidermidis were methicillin-resistant (MRSE), and 10 (37%) were ciprofloxacin-resistant. All but two MRSE isolates demonstrated multidrug resistance (MDR), and the staphylococcal cassette chromosome mec (SCCmec) type IVa was detected in five of the eight MRSE isolates. Clinical resolution of the ocular surface infection was reported in all 25 patients following treatment with besifloxacin. CONCLUSIONS: In this study, S. aureus contained few toxins, while SCCmec IVa and MDR was predominant among MRSE from ocular surface infections. Despite significant in vitro fluoroquinolone resistance, there were no cases of treatment failure with topical besifloxacin ophthalmic suspension 0.6%. FUNDING: Bausch Health US, LLC.

Loteprednol etabonate (submicron) ophthalmic gel 0.38% dosed three times daily following cataract surgery: integrated analysis of two Phase III clinical studies.

PURPOSE: To evaluate the efficacy and safety of a submicron formulation of loteprednol etabonate (LE) gel 0.38% instilled three times daily (TID) compared with vehicle for the treatment of inflammation and pain following cataract surgery with intraocular lens implantation, integrated across two multicenter, double-masked, randomized, parallel-group, Phase III studies. PATIENTS AND METHODS: Subjects ≥18 years of age with anterior chamber (AC) cells ≥grade 2 (6-15 cells) on day 1 after cataract surgery were randomized to receive 1 drop of LE gel 0.38% TID, twice daily (not reported/analyzed herein), or vehicle instilled in the study eye for 14 days. Primary endpoints were the proportion of subjects with resolution of AC cells and grade 0 (no) pain at postoperative day 8. Safety outcomes included adverse events (AEs), ocular signs, fundoscopy results, visual acuity, intraocular pressure (IOP), and tolerability (drop comfort and ocular symptoms). RESULTS: The integrated intent-to-treat population included 742 subjects (LE gel 0.38% TID, n=371; vehicle, n=371). Significantly more subjects in the LE gel 0.38% TID group compared with the vehicle group had complete resolution of AC cells (29.6% vs 15.1%) and grade 0 pain (74.4% vs 48.8%) at day 8 (P<0.0001 for both). LE gel 0.38% TID was safe and well tolerated, with only 1 LE-treated subject experiencing an IOP elevation ≥10 mm Hg. Most treatment-related AEs were mild and occurred less frequently with LE gel 0.38% than with vehicle. The majority (>75%) of subjects in each treatment group reported no drop discomfort. There were no reports of blurred vision with LE gel. CONCLUSION: The results of this integrated analysis indicate that LE (submicron) gel 0.38% administered TID is safe and effective for the treatment of ocular inflammation and pain following cataract surgery, with minimal risk of IOP elevation.

Antibiotic Resistance Among Pediatric-Sourced Ocular Pathogens: 8-Year Findings From the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) Surveillance Study.

BACKGROUND: The Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) study is a nationwide longitudinal antibiotic resistance surveillance program specific to bacterial pathogens commonly encountered in ocular infections. We evaluated in vitro resistance rates and trends among isolates obtained from pediatric patients (≤17 years of age). METHODS: Clinical centers across the United States were invited to submit ocular isolates of Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Haemophilus influenzae and Pseudomonas aeruginosa to a central laboratory. Minimum inhibitory concentrations for various antibiotic classes were determined by broth microdilution per Clinical and Laboratory Standards Institute guidelines and interpreted as susceptible, intermediate or resistant based on available breakpoints. Longitudinal trends were analyzed using a Cochran-Armitage test for linear trends in a proportion. RESULTS: Of 4829 isolates collected from January 2009 to December 2016, 995 isolates, sourced primarily from hospitals and referral centers, were obtained from pediatric patients (n = 286 H. influenzae, n = 284 S. aureus, n = 213 CoNS, n = 150 S. pneumoniae and n = 62 P. aeruginosa). With few exceptions, P. aeruginosa and H. influenzae were generally susceptible to the antibiotics tested. Of S. aureus and CoNS isolates, respectively, 56% and 72% were resistant to azithromycin and 24% and 47% were methicillin-resistant (MR); concurrent resistance to other drug classes and multidrug resistance (≥3 drug classes) were prevalent among MR staphylococci. Of S. pneumoniae isolates, 38% and 35% demonstrated resistance to azithromycin and penicillin, respectively. Besifloxacin had the lowest minimum inhibitory concentration against the Gram-positive isolates. CONCLUSIONS: These in vitro data suggest antibiotic resistance is common among staphylococcal and pneumococcal isolates collected from pediatric patients with ocular infections. Methicillin resistance was prevalent among staphylococci with many strains demonstrating multidrug resistance. These findings may not be representative of resistance trends in community-based practices.

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.

The Role of Nitric Oxide in the Intraocular Pressure Lowering Efficacy of Latanoprostene Bunod: Review of Nonclinical Studies.

Latanoprostene bunod (LBN) is a topical ophthalmic therapeutic for the reduction of intraocular pressure (IOP) in patients with open-angle glaucoma or ocular hypertension (OHT). LBN is composed of latanoprost acid (LA) linked to a nitric oxide (NO)-donating moiety and is the first NO-releasing prostaglandin analog to be submitted for marketing authorization in the United States. The role of latanoprost in increasing uveoscleral outflow of aqueous humor (AqH) is well established. Herein, we review findings from nonclinical studies, which evaluated the role of NO in the IOP-lowering efficacy of LBN. Pharmacokinetic studies in rabbits and corneal homogenates indicate that LBN is rapidly metabolized to LA and butanediol mononitrate (BDMN). NO is subsequently released by BDMN as shown by increased cyclic guanosine monophosphate (cGMP) levels in (1) the AqH and iris-ciliary body after administration of LBN in rabbits and in (2) human trabecular meshwork (TM) cells after incubation with LBN. LBN reduced myosin light chain phosphorylation, induced cytoskeletal rearrangement, and decreased resistance to current flow to a greater extent than latanoprost in TM cells, indicating that NO released from LBN elicited TM cell relaxation. LBN also lowered IOP to a greater extent than latanoprost in FP receptor knockout mice, rabbits with transient OHT, glaucomatous dogs, and primates with OHT. Along with results from a Phase 2 clinical study in which treatment with LBN 0.024% resulted in greater IOP-lowering efficacy than latanoprost 0.005%, these data indicate that LBN has a dual mechanism of action, increasing AqH outflow through both the uveoscleral (using LA) and TM/Schlemm's canal (using NO) pathways.

Evaluation of Efficacy and Safety of Brimonidine Tartrate Ophthalmic Solution, 0.025% for Treatment of Ocular Redness.

Purpose/Aims: This study assessed the efficacy and safety of brimonidine tartrate ophthalmic solution, 0.025% for treating ocular redness in adult subjects. MATERIALS AND METHODS: This was a single-center, double-masked, randomized, vehicle-controlled, parallel-group study in subjects ≥40 years, with ocular redness. Subjects were randomized 2:1 to brimonidine or vehicle, instilled QID for four weeks. Subjects completed four visits, the last occurring one week after treatment discontinuation. The investigator assessed ocular redness on a scale of 0-4 pre-instillation and 5-240 minutes post-instillation on Day 0, pre-instillation and 5 minutes post-instillation on Days 14 and 28, and on Day35; subjects assessed redness in diaries throughout the 28-day treatment period and following treatment discontinuation. Safety assessments included adverse events (AEs), rebound redness on treatment discontinuation, comprehensive ophthalmic exams, and vital signs. Drop comfort was assessed upon instillation, and 30 seconds and 1 minute post-instillation at Day 0. RESULTS: Fifty-seven subjects (brimonidine, n = 38; vehicle, n = 19) were randomized. Investigator-assessed ocular redness was significantly reduced with brimonidine across the entire post-instillation time period (overall treatment difference: -1.37; P < 0.0001) and at all individual time points (P < 0.0001). Subject-assessed ocular redness was also significantly lower with brimonidine (P ≤ 0.0005). No tachyphylaxis was evident. There were few ocular AEs, all mild to moderate in severity, and no redness rebound was observed upon brimonidine discontinuation. There were no effects on any safety measures, and both brimonidine and its vehicle were reported to be very comfortable. CONCLUSIONS: Brimonidine 0.025% appeared safe, well tolerated, and reduced ocular redness for at least 4 hours. No tachyphylaxis or rebound redness upon treatment discontinuation was observed.

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.

Loteprednol Etabonate 0.5%/Tobramycin 0.3% Compared with Dexamethasone 0.1%/Tobramycin 0.3% for the Treatment of Blepharitis.

PURPOSE: To compare the efficacy of loteprednol etabonate 0.5%/tobramycin 0.3% (LE/T) and dexamethasone 0.1%/tobramycin 0.3% (DM/T) ophthalmic suspensions in reducing select signs of blepharitis. METHODS: Data were pooled from two studies (one from the USA; one from China) of adults (n = 627) with blepharokeratoconjunctivitis treated with LE/T or DM/T four times daily for 2 weeks (safety population). Efficacy analyses included 495 eyes (247 LE/T, 248 DM/T) with any baseline sign of blepharitis. RESULTS: At Day 15, the least squares mean change from baseline in composite blepharitis severity was similar between LE/T (-2.86) and DM/T (-2.99) (90% CI for mean treatment difference: -0.35, 0.11). Intraocular pressure (IOP) increases ≥10 mmHg over baseline were reported for 1 US patient (DM/T group) and 19 Chinese patients (6 LE/T; 13 DM/T). CONCLUSIONS: LE/T was similarly effective in reducing the signs of blepharitis compared with DM/T, but demonstrated a better safety profile with respect to changes in IOP.

Antibiotic Resistance Among Ocular Pathogens in the United States: Five-Year Results From the Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) Surveillance Study.

IMPORTANCE: The Antibiotic Resistance Monitoring in Ocular Microorganisms (ARMOR) study is the only ongoing nationwide antibiotic resistance surveillance program specific to ocular pathogens. OBJECTIVE: To report resistance rates and trends among common ocular isolates collected during the first 5 years of the ARMOR study. DESIGN, SETTING, AND PARTICIPANTS: This antibiotic resistance surveillance study was performed at an independent central laboratory. Clinical centers across the United States were invited to submit ocular isolates of Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Streptococcus pneumoniae, Haemophilus influenzae, and Pseudomonas aeruginosa. Isolates were collected from January 1, 2009, through December 31, 2013, and analyzed from January 16 to May 15, 2015. MAIN OUTCOMES AND MEASURES: Minimum inhibitory concentrations for various antibiotic classes were determined by broth microdilution according to the guidelines of the Clinical and Laboratory Standards Institute. Minimum inhibitory concentrations were interpreted as susceptible, intermediate, or resistant based on established break points. RESULTS: A total of 3237 ocular isolates (1169 S aureus, 992 CoNS, 330 S pneumoniae, 357 H influenzae, and 389 P aeruginosa) were collected from 72 centers. Methicillin resistance was found among 493 S aureus isolates (42.2%; 95% CI, 39.3%-45.1%) and 493 CoNS isolates (49.7%; 95% CI, 46.5%-52.9%), and methicillin-resistant (MR) isolates had a high probability of concurrent resistance to fluoroquinolones, aminoglycosides, or macrolides (P < .001). Multidrug resistance to at least 3 additional antibiotic classes was found in 428 MR S aureus isolates (86.8%) and 381 MRCoNS isolates (77.3%). All staphylococcal isolates were susceptible to vancomycin. Resistance among S pneumoniae isolates was highest for azithromycin (113 isolates [34.2%]) whereas resistance among P aeruginosa and H influenzae was low against the antibiotics tested. Staphylococcal isolates from elderly patients were more likely to be MR, as were S aureus isolates obtained from the southern United States (P < .001). Methicillin resistance among staphylococci did not increase during the 5-year study period (P ≤ .22), and small decreases in resistance to ciprofloxacin among CoNS and MRCoNS and to tobramycin among CoNS (P ≤ .03) were found. CONCLUSIONS AND RELEVANCE: Methicillin resistance was prevalent among staphylococcal isolates from ocular infections, with many strains demonstrating multidrug resistance. These findings are consistent with resistance trends reported for nonocular staphylococcal isolates. Overall ocular resistance did not increase during the 5-year study period. Continued surveillance of ocular isolates provides critical information to guide selection of topical antibacterials used for empirical management of ocular infections.

Antibacterial efficacy of prophylactic besifloxacin 0.6% and moxifloxacin 0.5% in patients undergoing cataract surgery.

BACKGROUND: The purpose of this study was to investigate the ocular bacterial flora in patients scheduled to undergo cataract surgery and compare the antibacterial effects of besifloxacin ophthalmic suspension 0.6% and moxifloxacin ophthalmic solution 0.5% in these patients. METHODS: This was a prospective, randomized, laboratory-masked clinical trial. Patients received besifloxacin or moxifloxacin "quater in die" or QID (four times a day) for 3 days before cataract surgery in the surgical eye and 1 hour before surgery in the nonsurgical fellow eye. Conjunctival and eyelid swabs were obtained from both eyes at baseline and after treatment, on the day of surgery (Visit 2). Swabs were processed for bacterial colony counts (in terms of colony-forming units) and species identification. In vitro antibiotic susceptibilities of isolates were determined using Clinical and Laboratory Standards Institute breakpoints. RESULTS: Fifty-nine patients (n=28 besifloxacin, n=31 moxifloxacin) completed the study. The majority (73%) of conjunctival samples were culture negative at baseline. The most frequent isolates were coagulase-negative staphylococci (CoNS, 89%), specifically Staphylococcus epidermidis (72%). Both fluoroquinolones reduced the lid CFU values when administered QID for 3 days (P≤0.019), but only besifloxacin reduced the lid CFU estimate 1 hour following instillation of a single drop (P=0.039). Fewer besifloxacin-treated eyes had lids that were culture positive for CoNS at Visit 2 compared with moxifloxacin-treated eyes regardless of dosing regimen (P≤0.03). The minimum inhibitory concentration (MIC90) of besifloxacin against methicillin-resistant S. epidermidis (MRSE) was eightfold lower than that of moxifloxacin. CONCLUSION: Besifloxacin appeared more effective in reducing bacterial counts on eyelids of patients undergoing cataract surgery, with significant reductions as early as 1 hour postdose, compared with moxifloxacin. Besifloxacin was more active in vitro against MRSE.

Development of a non-settling gel formulation of 0.5% loteprednol etabonate for anti-inflammatory use as an ophthalmic drop.

The eye has protective barriers (ie, the conjunctival and corneal membranes) and defense mechanisms (ie, reflex tearing, blinking, lacrimal drainage) which present challenges to topical drug delivery. Topical ocular corticosteroids are commonly used in the treatment of anterior segment diseases and inflammation associated with ocular surgery, and manufacturers continually strive to improve their characteristics. We describe the development of a novel ophthalmic gel formulation of loteprednol etabonate (LE), a C-20 ester-based corticosteroid with an established safety profile, in the treatment of ocular inflammatory conditions. The new LE gel formulation is non-settling, eliminating the need to shake the product to resuspend the drug, has a pH close to that of tears, and a low preservative concentration. The rheological characteristics of LE gel are such that the formulation is instilled as a drop and transitions to a fluid upon instillation in the eye, yet retains sufficient viscosity to prolong ocular surface retention. The new formulation provides consistent, uniform dosing as evidenced by dose extrusion studies, while pharmacokinetic studies in rabbits demonstrated rapid and sustained exposure to LE in ocular tissues following instillation of LE gel. Finally, results from two clinical studies of LE gel in the treatment of postoperative inflammation and pain following cataract surgery indicate that it was safe and effective. Most patients reported no unpleasant drop sensation upon instillation, and reports of blurred vision were rare.

Besifloxacin ophthalmic suspension 0.6% in the treatment of bacterial conjunctivitis patients with Pseudomonas aeruginosa infections.

BACKGROUND: The purpose of this study was to determine the efficacy of besifloxacin ophthalmic suspension 0.6% when used in the treatment of bacterial conjunctivitis infections due to Pseudomonas aeruginosa. METHODS: We undertook a post hoc analysis of clinical outcomes in patients with bacterial conjunctivitis due to P. aeruginosa across four prospective, multicenter, double-masked, randomized, controlled, clinical studies of besifloxacin ophthalmic suspension 0.6%. Efficacy outcomes included bacterial eradication and clinical resolution of the baseline infection at follow-up visits. Bacterial eradication was defined as the absence of ocular bacterial species present at or above threshold at baseline, while clinical resolution was defined as grade 0 ocular discharge and bulbar conjunctival injection. Safety outcomes included the incidence of adverse events, changes in visual acuity, and biomicroscopy and ophthalmoscopy findings. Patient outcomes were summarized and bacterial eradication and clinical resolution rates integrated. RESULTS: Of 1317 patients with culture-confirmed bacterial conjunctivitis across four clinical studies, nine (0.7%) were infected with P. aeruginosa at baseline, and of these, five were randomized to treatment with besifloxacin ophthalmic suspension 0.6%. Bacterial eradication of the baseline infection was observed at both follow-up visits in all five patients. Clinical resolution was achieved in two of five patients by the first follow-up visit and four of five patients by the second follow-up visit. There were no adverse events reported in these patients. There were no clinically meaningful biomicroscopy findings or changes in ophthalmoscopy or visual acuity. CONCLUSION: The incidence of bacterial conjunctivitis due to P. aeruginosa was low. Treatment of patients with P. aeruginosa infections with besifloxacin ophthalmic suspension 0.6% led to bacterial eradication of P. aeruginosa by the first follow-up visit and high rates of clinical resolution.

Advances in corticosteroid therapy for ocular inflammation: loteprednol etabonate.

Topical corticosteroids are effective in reducing anterior segment inflammation but are associated with adverse drug reactions (ADRs) including elevation of intraocular pressure (IOP) and cataract formation. Retrometabolic drug design has advanced the development of new corticosteroids with improved therapeutic indices. Engineered from prednisolone, loteprednol etabonate (LE) has a 17α-chloromethyl ester, in lieu of a ketone group, and a 17ß-etabonate group. LE is highly lipophilic and binds with high affinity to the glucocorticoid receptor; any unbound LE is metabolized to inactive metabolites. LE has been studied in several anterior segment inflammatory conditions (giant papillary conjunctivitis, allergic conjunctivitis, anterior uveitis, and keratoconjunctivitis sicca), and in postoperative ocular inflammation and pain. Combined with tobramycin, it is effective in blepharokeratoconjunctivitis. Elevations in IOP are infrequent with LE, and the absence of a C-20 ketone precludes formation of Schiff base intermediates with lens proteins, a common first step implicated in cataract formation with ketone steroids.

Safety and tolerability of loteprednol etabonate 0.5% and tobramycin 0.3% ophthalmic suspension in pediatric subjects.

BACKGROUND: Loteprednol etabonate 0.5% and tobramycin 0.3% ophthalmic suspension (LE/T) is indicated for steroid-responsive inflammatory ocular conditions where superficial bacterial ocular infection or a risk of bacterial ocular infection exists. LE/T was shown to be safe in healthy volunteers and patients aged 18 years and older with minimal effect on intraocular pressure (IOP). OBJECTIVE: The aim of the study was to evaluate the safety of LE/T in pediatric subjects by examining data from two clinical studies. METHODS: Two randomized, multicenter, double-masked, parallel-group (one two-arm, the other four-arm) studies were conducted in subjects aged 0-6 years (N = 245). One study assessed LE/T compared with vehicle in the management of lid inflammation (n = 108) and the other compared LE/T with loteprednol etabonate ophthalmic suspension 0.5% (LE), tobramycin ophthalmic solution 0.3% (tobramycin), and vehicle in the treatment of blepharoconjunctivitis (n = 137). In the first study, subjects were randomized to LE/T or vehicle administered four times daily (qid) for the first 7 days followed by twice daily (bid) for 7 days along with warm compresses bid for the entire 2 weeks. In the second study, subjects were randomized to LE/T, LE, tobramycin, or vehicle administered qid for 14 days. Treatment-emergent ocular and non-ocular adverse events (AEs) and bilateral vision were assessed at all study visits in both studies. In addition, in the lid inflammation study, IOP was assessed at all visits. The primary safety endpoint in both studies was the incidence of treatment-emergent AEs. RESULTS: The incidence of LE/T treatment-emergent AEs was low. A total of four ocular AEs were reported for three LE/T-treated subjects in the first study (conjunctivitis [two events], meibomian gland dysfunction, and corneal staining), and one ocular AE was reported for an LE/T-treated subject in the second study (eye pain). A total of 13 non-ocular AEs were reported for eight LE/T-treated subjects in the two trials. The most prevalent non-ocular AEs were pyrexia (three events) and rash (two events). There were no differences in the incidence of specific ocular and non-ocular AEs between the LE/T group and the comparator treatment group. In both studies, there were no clinically meaningful reductions in vision at follow-up visits. Mean IOP and IOP changes from baseline, assessed in the lid inflammation study, were not different between LE/T and vehicle treatment groups at any study visits. CONCLUSION: The results of these two clinical trials demonstrate the short-term safety of treatment with topical LE/T in pediatric subjects (0-6 years of age) with lid inflammation or blepharoconjunctivitis.

Integrated analysis of three bacterial conjunctivitis trials of besifloxacin ophthalmic suspension, 0.6%: microbiological eradication outcomes.

PURPOSE: To assess clinical antimicrobial efficacy results obtained with besifloxacin ophthalmic suspension, 0.6%, administered three times a day (TID) for 5 days, integrated across three clinical trials of bacterial conjunctivitis and to investigate any microbiological eradication failures. METHODS: Clinical microbiological eradication data from three randomized, double-masked, parallel group studies of patients with bacterial conjunctivitis (two vehicle controlled; one active controlled with moxifloxacin ophthalmic solution, 0.5%) were integrated. All bacterial samples isolated at baseline above the species-specific threshold value were subjected to antimicrobial susceptibility testing. Samples isolated at subsequent visits were subjected to susceptibility testing and pulsed-field gel electrophoresis (PFGE) to investigate the cause of eradication failures and the potential for drug resistance development. RESULTS: Visit 2 (day 4 or 5) and visit 3 (day 8) overall microbiological eradication rates were 92.2% and 88.4% for besifloxacin ophthalmic suspension compared with 61.4% and 72.5% for vehicle and 91.6% and 85.7% for moxifloxacin ophthalmic solution. Visit 2 and visit 3 microbiological eradication rates for Gram-positive and Gram-negative isolates and for individual species were consistent with the overall eradication rates. The majority of observed eradication failures in any treatment group were due to the persistence of the pathogen isolated at baseline. Eradication failures in the besifloxacin treatment group were not associated with lower antimicrobial susceptibility at baseline. PFGE data showed that the majority of bacterial strains in eyes with eradication failures were identical to the strain isolated at baseline; these eradication failures were not associated with a lower antimicrobial susceptibility at the follow-up visit. CONCLUSION: Treatment with besifloxacin ophthalmic suspension, 0.6%, administered TID for 5 days resulted in microbiological eradication rates that were ≥ 90% across the three clinical studies for the common pathogens of bacterial conjunctivitis. The few eradication failures were not due to fluoroquinolone resistance at baseline and/or resistance development during treatment.