Study of the Effectiveness of Multipurpose Solutions on the Bacterial Disinfection of Silicone Hydrogel Contact Lenses In Vitro.

OBJECTIVES: To assess the antimicrobial effectiveness of multipurpose solutions in regard to the disinfection of silicone hydrogel contact lenses (CL) using a study of clinical bacterial isolates from ocular material. METHODS: Three multipurpose solutions (solution A: polyhexamethylene biguanide 0.00025 g/100 mL; solution B: polyquaternary-1 0.001% and myristamidopropyl dimethylamine 0.0006%; and solution C: polyaminopropyl biguanide 0.00013% and polyquaternary 0.0001%) were used as a 3-phase disinfection on silicone hydrogel CL contaminated with bacteria from clinical isolates that were divided into five groups (group 1: Pseudomonas aeruginosa; group 2: Staphylococcus aureus; group 3: Staphylococcus epidermidis; group 4: Streptococcus spp; and group 5: enterobacteria). RESULTS: No differences were observed between the 24- and 48-hr measurements in any of the samples, and the positivity of microorganisms in T0 was 100% for all solutions; it was 0% in T3. Therefore, only steps T1 (rubbing followed by rinsing) and T2 (rubbing followed by rinsing and immersion of CL into solution) were considered for analysis at the 24-hr measurement time. Throughout the phases, a decrease in the number of bacteria was observed, culminating in the elimination (no recovery) of all microorganisms in the three solutions. CONCLUSIONS: At the end of the proposed process, the tested solutions were effective.

In vitro antimicrobial analysis of aqueous humor after topical application of moxifloxacin hydrochloride 0.5%.

PURPOSE: To evaluate the in vitro antimicrobial activity of aqueous humor in patients who had preoperative topical application of moxifloxacin hydrochloride 0.5%. SETTING: Department of Ophthalmology, Santa Casa de Misericórdia de São Paulo, Brazil. DESIGN: Comparative case series. METHODS: Twenty-nine eyes from 29 cataract surgery patients were included in this study. In the study group (n = 15 eyes), 3 topical applications of moxifloxacin hydrochloride 0.5% were administered preoperatively; in the control group (n = 14 eyes), no topical applications were administered. Aqueous humor samples were collected and stored in sterile microtubes at -80°C until analysis. Antimicrobial analysis was performed using standard strains with standard sterile filter paper disks. Inhibition halos were measured in millimeters, and both bactericidal and bacteriostatic effects were analyzed. RESULTS: Inhibition halos were observed on most of the study group plates except those with Streptococcus pneumoniae: Escherichia coli (13.93 mm ± 0.64 [SD]), Klebsiella pneumoniae (10.63 ± 0.61 mm), Staphylococcus aureus (7.47 ± 0.68 mm), and S epidermidis (4.20 ± 3.33 mm) The differences between the mean inhibition halo diameters were statistically significant (P < .0001) in all samples. No bactericidal effect was observed against any of the microorganisms studied. CONCLUSIONS: After topical application of moxifloxacin 0.5%, aqueous humor showed bacteriostatic effect against E coli, K pneumoniae, S aureus, and S epidermidis. No bactericidal effect was observed against any of the microorganisms evaluated. No antimicrobial effect against S pneumoniae was observed. FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.

In Vitro Antimicrobial Long-Term Evaluation of Corneal Preservation Media Against Microorganisms Using A Closed-Chamber Study Model.

PURPOSE: To evaluate the existence of in vitro long-term antimicrobial activity of Optisol-GS against microorganisms related to corneal infection using a closed-chamber study model. METHODS: Optisol-GS was contaminated with microorganisms related to corneal infections, and different times after contamination was analyzed using a closed-chamber study model. Microbial growths were analyzed by macroscopic observation. RESULTS: For Staphylococcus aureus and Pseudomonas aeruginosa, bacterial growth was observed in samples taken 1 hour through 7 days and 14 days after contamination occurred. For Staphylococcus epidermidis, Streptococcus agalactiae, and Candida albicans, microbial growth was observed in all samples studied. For Streptococcus pneumoniae, bacterial growth was observed in samples taken 1 hour through 72 hours after contamination. For Streptococcus pyogenes, bacterial growth was observed in samples taken 1 hour through 7 days after contamination. For Escherichia coli, bacterial growth was observed in samples taken 1 hour through 48 hours after contamination occurred. CONCLUSIONS: We conclude that no in vitro antimicrobial effect for any microorganism analyzed was observed in contaminated Optisol-GS after 72 hours; however, effective antimicrobial activity was observed for S. aureus, Str. pneumoniae, Str. pyogenes, P. aeruginosa, and E. coli after 7 to 10 days.

Antibacterial properties of cyanoacrylate tissue adhesive: Does the polymerization reaction play a role?

PURPOSE: To ascertain if the polymerization reaction also contributes additionally to the antibacterial effects of two commonly used cyanoacrylate tissue adhesives. MATERIALS AND METHODS: Fresh liquid ethyl-cyanoacrylate (EC) and N-butyl-cyanoacrylate (BC) adhesives were applied onto 6-mm sterile filter paper discs. In the first group, the adhesive-soaked discs were immediately placed onto confluent monolayer cultures of bacteria, allowing the polymerization reaction to proceed while in culture. In the second group, the adhesive-soaked disc was allowed to first polymerize prior to being placed onto the bacterial cultures. Four types of bacteria were studied: Staphylococcus aureus, Streptococcus pneumoniae, Escherichia coli, and Pseudomonas aeruginosa. Immediately after the discs were applied, the cultures were incubated at 35 degrees C for 24 h. Bacterial inhibitory halos were measured in the cultures at the end of the incubation period. RESULTS: For EC, exposure of the bacteria to the cyanoacrylate polymerization reaction increased the bacterial inhibitory halos in Streptococcus pneumonia, Staphylococcus aureus and Escherichia coli. For BC, it increased the bacterial inhibitory halos in Staphylococcus aureus and Streptococcus pneumoniae. No inhibitory halos were observed in Pseudomonas aeruginosa. The bactericidal effect was higher in actively polymerizing EC, compared to previously polymerized EC in Staphylococcus aureus, Streptococcus pneumoniae, and Escherichia coli; however, no such differences were observed for BC. CONCLUSIONS: The polymerization reaction may also be an important factor in the antibacterial properties of EC and BC.