Differential Antimicrobial Efficacy of Multipurpose Solutions against Acanthamoeba Trophozoites

Abstract

SIGNIFICANCE This investigation examines the effectiveness of several common contact lens solutions in the disinfection of Acanthamoeba , which causes a serious eye infection most often resulting from dysfunctional or improper use of contact lens products. PURPOSE Acanthamoeba keratitis is an eye infection caused by a free-living amoeba, which can lead to extensive corneal damage and frequently blindness. Acanthamoeba keratitis is linked with contact lens use combined with noncompliance with contact lens care cleaning regimens. The patient's choice and use of multipurpose solutions (MPSs) continue to be a risk factor for Acanthamoeba keratitis. Thus, it is critical that the Acanthamoeba disinfection efficacy of the popular MPSs be determined. Here we compare the efficacy of seven major MPSs on the global market. METHODS Using standard methods of Acanthamoeba disinfection and quantification, Acanthamoeba ATCC 30461, 30868, 50370, and 50676 trophozoites were inoculated into each MPS and held for the manufacturer's recommended disinfection time. Acanthamoeba recovery plates were incubated for 14 days, after which positive wells were identified and cell concentrations determined using the 50% endpoint method. RESULTS Members of the OPTI-FREE products (Express, Replenish, and Puremoist [Alcon, Fort Worth, TX]) demonstrated significantly higher percentages of antimicrobial activity compared with the renu Advanced Formula (Bausch + Lomb, Rochester, NY), Biotrue (Bausch + Lomb), Acuvue RevitaLens (Johnson & Johnson, Santa Ana, CA), and Lite products (Cooper Vision, Scottsville, NY) for four of the trophozoite strains tested. CONCLUSIONS Many of the popular MPS biocides maintain little or no antimicrobial activity against Acanthamoeba trophozoites, and the number of biocides in an MPS does not necessarily indicate its antimicrobial activity.

Reduction of disinfection efficacy of contact lens care products on the global market in the presence of contact lenses and cases

“…However, while this range of potential contamination activities are ever-present, it’s important that the CLC solutions commonly available to consumers are able to robustly disinfect lenses when used as directed, to otherwise protect patients against the micro-organisms that their lenses may come in contact with. Additionally, it is equally important that products are not only tested in the test tube stand-alone scenario, but also in the real-world common-use scenario involving contact lenses and cases, and that they maintain similar disinfection efficacy to the oft-reported stand-alone results 9 13. It has previously been shown that contact lenses themselves, as well as the contact lens cases packaged with CLCs, can take up biocide out of solution, thereby making any CLC less effective in this real-world situation 7 19…”

“…Further, while no standard yet exists for determining disinfection efficacy against Acanthamoeba , a protocol for examining this is currently being developed by the American National Standards Institute (ANSI) 14 . Acanthamoeba can also be considered a difficult and differentiating organism to outline the overall disinfection efficacy of any CLC 13 15 16…”

“…As previously described, 13 trophozoites were axenically cultured in AC6 media (axenic culture medium; containing 20 g biosate peptone, 5 g glucose, 0.3 g KH 2 PO 4 , 10 ug vitamin B 12 , and 1 glass 5 mg L-methionine per litre of distilled deionised water). AC6 was adjusted to a pH 6.6-6.95 with 1M NaOH and autoclaved at 121°C for 20 min before being stored at room temperature for use within 2 months.…”

Complete Recovery of Acanthamoeba Motility among Surviving Organisms after Contact Lens Care Disinfection

“…As evidenced by the increase in the number of investigations into, and publications on Acanthamoeba keratitis in recent years [ 5 , 6 , 8 , 10 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 ], this is a devastating and potentially sight-threatening disease. However, until now there has been a lack of investigation regarding the behavior of Acanthamoeba on contact lenses, both in and out of contact lens care disinfecting solutions (CLCs).…”

The Activity of PHMB and Other Guanidino Containing Compounds against Acanthamoeba and Other Ocular Pathogens

“…However, in commercially available MPS, activity is variable even in solutions containing similar formulations of antimicrobial agents [ 6 , 7 , 8 , 9 ]. To overcome this issue, there are newer formulations of MPS, including ACUVUE™ RevitaLens (JnJvision, Jacksonville, FL, USA), which combines the biguanide alexidine with the quaternary ammonium compound polyquaternium-1 (PQ-1), and Biotrue ® (Bausch & Lomb, Rochester, NY, USA), which combines the polyaminopropyl-biguanide (PAPB) with PQ-1 to increase antimicrobial activity.…”