Biocidal Efficacy of a Hydrogen Peroxide Lens Care Solution Incorporating a Novel Wetting Agent.

PURPOSE: To compare the antimicrobial effects of CLEAR CARE, a 3% hydrogen peroxide (H2O2) solution formulated for simultaneous cleaning, daily protein removal, disinfection, and storage of soft (hydrophilic) hydrogel, silicone hydrogel, and gas-permeable contact lenses, and CLEAR CARE PLUS, consisting of the 3% H2O2 solution plus a novel wetting agent, polyoxyethylene-polyoxybutylene (EOBO-21). METHODS: Three lots each of the 2 solutions were incubated with 5 compendial microorganisms required by the Food and Drug Administration (FDA) 510(k) and International Organization for Standardization (ISO) 14729 stand-alone procedures, 4 clinical isolates of Gram-positive and Gram-negative bacteria, and trophozoites and cysts of 2 Acanthamoeba strains that are associated with microbial keratitis. Microbial loads were evaluated after disinfection and neutralization. RESULTS: Both solutions exceeded the FDA/ISO stand-alone primary criteria against Gram-positive and Gram-negative compendial bacteria, yeast, and mold after only 1.5-hr disinfection/neutralization. At the recommended minimum disinfection time, bacteria were reduced by 4.4 to 5.1 logs, yeast by 4.4 to 4.9 logs, and mold by 2.9 to 3.5 logs with and without organic soil. In addition, both solutions eliminated or effectively reduced populations of clinically relevant ocular bacterial isolates (4.5-5.0 logs), Acanthamoeba trophozoites (3.4-4.2 logs), and cysts (1.5-2.1 logs). CONCLUSION: Both solutions eliminated or reduced populations of FDA/ISO compendial bacteria and fungi as well as clinically relevant microorganisms and Acanthamoeba trophozoites and cysts. The addition of EOBO-21 to the 3% H2O2 lens care solution had no impact on antimicrobial activity.

Antimicrobial Efficacy of Multipurpose Disinfecting Solutions in the Presence of Contact Lenses and Lens Cases.

OBJECTIVE: The aim of this study was to use antimicrobial efficacy endpoint methodology to determine compatibility of multipurpose disinfecting solutions (MPSs), lens cases, and hydrogel lenses for disinfection (AEEMC) against International Organization for Standardization (ISO)-specified microorganisms and clinical ocular isolates of Stenotrophomonas maltophilia. METHODS: Six MPSs (PQ/Aldox 1, 2, and 3; PQ/Alexidine; PQ/PHMB; and PHMB) were challenged against ISO-specified microorganisms and S. maltophilia using the AEEMC test. AEEMC tests were performed with and without balafilcon A, etafilcon A, and senofilcon A lenses in lens cases with organic soil. Exposure times included disinfection time (DT) and 24 hr. Additionally, all six MPSs were challenged with two strains of S. maltophilia, based on the ISO Stand-alone test. RESULTS: The efficacy against bacteria for PQ/Aldox and PQ/Alexidine MPSs was not diminished by the presence of lenses. The efficacy of PQ/PHMB and PHMB MPSs against Serratia marcescens was significantly reduced compared with the no-lens control at DT for at least one lens type. The PHMB MPS with lenses present also demonstrated reduced efficacy against Staphylococcus aureus at DT versus the control. PQ/Aldox MPSs retained activity against Fusarium solani with lenses present; however, all other test MPSs demonstrated reduced F. solani efficacy at DT with lenses present. With lenses, all MPSs showed reduced efficacy against Candida albicans. CONCLUSIONS: AEEMC antimicrobial efficacy test results vary based on challenge microorganism, contact lenses, and MPS biocide systems. This study highlights the importance of evaluating MPSs for compatibility with lenses and lens cases.

DNA sequencing by Microseq kit targeting 16S rRNA gene for species level identification of mycobacteria.

BACKGROUND & OBJECTIVES: Identification of mycobacteria to the species level is of therapeutic significance. Conventional methods are laborious and time consuming so we did 16S rRNA sequencing using a commercial MicroSeq sequencing kit, which includes DNA sequencing with software package for identification and phylogenetic analysis of clinical mycobacterial isolates. METHODS: A total of 47 mycobacteria were tested by both conventional and genotypic method using commercially available MicroSeq 500 amplification kit assay. The identification was determined by comparing the 500 bp amplified product of 16S rDNA sequence to the MicroSeq database. RESULTS: The phenotypic identification was concordant with genotypic identification in 33 (70.2%) isolates of 14 Mycobacterium tuberculosis, 11 M. fortuitum, 7 M. abscessus and 1 M. duvalii. For the discrepant isolates, identification was possible only by DNA sequencing in 14 (29.7%) isolates. The 14 discrepant isolates were 5 M. farcinogenes, 3 M. genavense, 2 M. species. nov and 1 each of M. fortuitum, M. immuogenum, M. simiae and M. wolinskyi. Of these, five were uncommon species that were difficult to identify by phenotypic method. INTERPRETATION & CONCLUSION: The MicroSeq DNA sequencing is an excellent tool for species identification of mycobacteria, which reduces the turn around time, makes repeat analysis easy as compared to phenotypic identification specially for mycobacterial isolates with ambiguous biochemical profiles.

Safety and efficacy of moxifloxacin-dexamethasone eyedrops as treatment for bacterial ocular infection associated with bacterial blepharitis.

INTRODUCTION: Treatments that offer two medications in a fixed combination have the potential to offer efficacious and safe treatment with advantages such as a regimen that is simpler than administering two separate solutions. This study evaluated the safety and efficacy of fixed-combination versus concomitant moxifloxacin 0.5% and dexamethasone 0.1% ocular solutions for the treatment of bacterial ocular inflammation and infection. METHODS: The clinical study design was a randomized, double-masked, active-controlled, parallel-group trial of 102 subjects with bacterial blepharitis in which two patients also had bacterial conjunctivitis. All subjects received two bottles of study medication: either a fixed combination of moxifloxacin 0.5%/dexamethasone 0.1% ophthalmic solution and placebo eye drops (fixed-dose group), or moxifloxacin 0.5% ophthalmic solution and dexamethasone 0.1% (concomitant group). One drop of each study medication was instilled bilaterally four times per day for 7 days. Clinical resolution, signs, symptoms, and safety were assessed. Microbiological specimens were collected from the eyelid margin and conjunctivae of each eye from each patient at the time of enrollment and at the exit visit. RESULTS: Clinical resolution occurred similarly in both groups (81.6% of eyes, fixed-dose group; 82.3% of eyes, concomitant group). Moreover, the microbiological efficacy of the treatment was also similar for both the fixed-dose group (84%) and the concomitant group (83%). Ocular symptoms and signs improved over time, with no significant differences between groups after 7 days of treatment, except the fixed-dose group had significantly more eyes with clinical resolution in eyelid erythema (100%, n = 98/98, fixed-dose group; 92.7%, n = 89/96, concomitant group; P = 0.0194) and eyelid scaling/crusting (98%, n = 96/98, fixed-dose group; 89.6%; n = 86/96 eyes, concomitant group; P = 0.0337). Both regimens were safe and well tolerated. CONCLUSION: The fixed-dose combination of moxifloxacin, 0.5% and dexamethasone, 0.1% was therapeutically equivalent and as well tolerated as the concomitant dosage.

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.

A highly virulent Staphylococcus aureus: rabbit anterior chamber infection, characterization, and genetic analysis.

PURPOSE: To describe and characterize a Staphylococcus aureus strain with unique virulence that overcomes host defenses of the rabbit anterior chamber and mimics clinical cases of postcataract surgery endophthalmitis. METHODS: Nine isolates of S. aureus were tested to determine their viability in the rabbit anterior chamber. Growth of UMCR1 in the anterior chamber was established and expressed as log colony-forming units per milliliter of aqueous humor. Pathologic changes produced by UMCR1 were documented by photographs, slit lamp examination, histopathologic analysis, and quantification of neutrophils. UMCR1 was characterized by antibiotic susceptibility, biochemical tests, ribotyping, genome restriction mapping, and multilocus sequence typing (MLST). RESULTS: UMCR1 was the only S. aureus strain that grew within the anterior chamber, reaching log 6.97 ± 0.18 CFU/mL by 16 hours after infection. Pathologic changes included conjunctival injection, chemosis, corneal edema, severe iritis, fibrin accumulation, and a 193-fold increase in neutrophils by 16 hours after infection. UMCR1 was only resistant to sulfamethoxazole and, like other S. aureus isolates, polymyxin B. UMCR1 also had biochemical reactions and a ribotype pattern typical of S. aureus. The genomic reconstruction analysis of UMCR1 was most similar to strains MW2 and MSSA476. MLST revealed a 1 in 3198 nucleotide difference between UMCR1 and strains MW2 and MSSA476. CONCLUSIONS: This study describes a unique S. aureus strain that overcomes host defenses and replicates in the anterior chamber. The survival and growth of this organism could be used for studies of S. aureus pathogenesis, host defenses, and effectiveness of antibiotics within the anterior chamber.

Pseudomonas otitidis sp. nov., isolated from patients with otic infections.

A novel Pseudomonas species, for which the name Pseudomonas otitidis sp. nov. is proposed, was identified from clinical specimens of infected human ears. Forty-one pseudomonads (34 from patients with acute otitis externa, six from patients with acute otitis media with otorrhoea and one from a patient with chronic suppurative otitis media) were recovered that did not match any known species. On the basis of genetic analyses and biochemical characterization, these isolates were shown to belong to the genus Pseudomonas. 16S rRNA gene sequence analysis and DNA-DNA hybridization studies indicated that this novel bacterium is closely related to, but different from, Pseudomonas aeruginosa. A description of this species is based on polyphasic studies of 11 clinical isolates. The type strain of Pseudomonas otitidis is MCC10330T (=ATCC BAA-1130T = DSM 17224T).

Characterization of Mycobacterium montefiorense sp. nov., a novel pathogenic Mycobacterium from moray eels that is related to Mycobacterium triplex.

The characterization of a novel Mycobacterium sp. isolated from granulomatous skin lesions of moray eels is reported. Analysis of the hsp65 gene, small-subunit rRNA gene, rRNA spacer region, and phenotypic characteristics demonstrate that this organism is distinct from its closest genetic match, Mycobacterium triplex, and it has been named M. montefiorense sp. nov.