- Email: [email protected]
Antimicrobial efficacy of multipurpose disinfecting solutions against clinical isolates after prolonged storage
Poster abstracts / Contact Lens & Anterior Eye 36 (2013) e16–e46
improved formulations for eradicating biofilms from contact lens cases. http://dx.doi.org/10.1016/j.clae.2013.08.136 74 Antimicrobial efficacy of multipurpose disinfecting solutions against clinical isolates after prolonged storage Marina Milenkovic (Bs) ∗ , Nancy Brady (Bs), Anthony Lam (Bs), James Cook (Bs) E-mail address: [email protected] (M. Milenkovic). Purpose: To compare antimicrobial efficacy of commercially available multipurpose disinfecting solutions (MPS) against Gramnegative clinical isolates following prolonged storage in lens case in the presence of a lens. Method: The multipurpose disinfecting solutions studied were - MPS-1: polyquaternium (PQ1) + alexidine dihydrochloride (ALX), MPS-2: PQ1 + polyhexamethylene biguanide (PHMB), MPS-3: PQ1 + myristamidopropyl dimethylamine (ALDOX) and MPS-4: PQ1 + ALDOX+ nonanoyl ethylenediaminetriacetic acid (EDTA). Test solutions were inoculated with Gram-negative clinical isolates in the appropriate lens case, in the presence of Acuvue2 (etafilcon A) lens. Test solution efficacy was evaluated at minimum recommended manufacturer disinfection time of6 hours and following prolonged storage. Test solutions were also inoculated with Gram-negative clinical isolates in the test tube and tested according to ISO 14729. Results: After 6 hours exposure, MPS-1 and MPS-2 showed > 3 log kill against clinical isolates in a test tube, while MPS- 3 and MPS4 failed stand-alone criteria. MPS-1 and MPS- 2 maintained efficacy in the lens case in the presence of Acuvue2 lens and achieved > 2.5 log kill. MPS-3 and MPS-4 showed < 1 log kill or organism regrowth at 6 hours exposure. Following 7 days storage in a lens case, MPS1 achieved > 3 log kill for all organisms tested. MPS-2 and MPS-3 failed to achieve 3 log kill for one organism tested. MPS-4 failed to achieve 3 log kill for two organisms tested. Following 30 days storage in a lens case, MPS-1, MPS-2 and MPS-3 achieved > 3 log kill for all organisms tested, while MPS-4 failed to achieve 3 log kill for two organisms tested. Conclusions: Gram-negative clinical isolates are resistant to MPS-3 and MPS-4. MPS-1 and MPS-2 showed ability to reduce microbial load under worst case conditions, tested in a lens case with Acuvue2 lens present http://dx.doi.org/10.1016/j.clae.2013.08.137 75 In vitro efficiency of contact lens care solutions in removing cholesterol deposits from silicone hydrogel contact lenses Lakshman Subbaraman (PhD, BSOptom, MSc, FAAO) ∗ , Hendrik Walther (MSc), Lise Kay (BSc), Lyndon Jones (PhD, FCOptom, FAAO) E-mail address: [email protected] (L. Subbaraman). Purpose: To determine the efficiency of multi- purpose solutions (MPS) and saline in removing cholesterol deposits from silicone hydrogel (SH) contact lens materials using an in vitro model. Method: Six SH lens materials: senofilcon A, comfilcon A, balafilcon A, lotrafilcon A, lotrafilcon B and lotrafilcon B toric were removed from the blister pack, incubated for 7 days at 37 ◦ C in an artificial tear solution (ATS) containing 14-C radi-
e41
olabelled cholesterol. Thereafter, lenses were cleaned with an unpreserved saline solution (Sensitive Eyes) or one of five MPS (Opti-Free® PureMoist®, renu fresh, RevitaLens, Biotrue, SoloCare Aqua), according to the manufacturer recommendations, and stored in a vial containing the MPS. Lenses were then extracted with 2:1 chloroform:methanol, radioactive counts were determined and g/lens of cholesterol was determined. Results: Balafilcon A and senofilcon A showed the highest amounts of cholesterol deposition before cleaning (0.93 ± 0.02 g/lens, 0.95 ± 0.01 g/lens respectively), while lotrafilcon A and lotrafilcon B deposited the lowest amounts (0.37 ± 0.03; 0.47 ± 0.12). OptiFree PureMoist removed more cholesterol than the other solutions for all lens materials combined (p < / = 0.009); however, the amount of cholesterol removedwassignificantforindividuallensmaterialsbalafilcon A and senofilcon A (p = 0.006 and p = 0.042). Sensitive Eyes saline and other MPS evaluated showed no significant effect on lipid removal from the lenses tested (p > 0.05). Conclusions: Lipid-removal efficacy varies depending on the combination of lens material and solution. Only one MPS showed a significant reduction in cholesterol deposition for any of the lenses tested. It will be valuable to conduct further work to determine the efficacy of MPS in removing lipid deposits on worn lenses and how these deposits may impact subjective comfort. http://dx.doi.org/10.1016/j.clae.2013.08.138 76 Formation of biofilms of Stenotrophomonas maltophilia and Pseudomonas aeruginosa on contact lenses Mark Willcox (BSc, PhD) ∗ , Ajay Vijay (BOptom, PhD) E-mail address: [email protected] (M. Willcox). Purpose: Contact lens cases can become contaminated with high levels of Gram-negatives (e.g. S. maltophilia). Amount of contamination is dependent on the type of multipurpose disinfecting solution (MPDS) that is used, (certain MPDS containing Polyquaternium/Aldox have highest contamination). High levels of Gram-negative case contamination are associated with higher levels of infiltrates during lens wear. Bacteria colonise contact lenses and are transferred into the eye. Our aim was to determine the ability of S. maltophilia and Pseudomonas aeruginosa to form biofilms on contact lenses. Method: Clinical isolates of S. maltophilia and P. aeruginosa were grown, suspended at 1.0 x105 to 1.0 x109 cfu/ml and allowed to adhere to lenses (silicone hydrogel high Dk or HEMA-based low Dk). Numbers of cells on lenses were examined by culture. Effect of wear on bacterial adhesion was assessed after 1 day lens wear. Subjects signed informed consent and the Declaration of Helsinki for use of human subjects was followed. Results: Adhesion of P. aeruginosa to low or high Dk lenses increased with increasing inoculum, reaching a maximum (6 log cfu/lens) when 1x109 cells were added to high Dk lenses. Each 10 fold increase in inoculum resulted in 10 fold increase in adhesion to lenses. For S. maltophilia, adhesion was maximal when 1x105 cells were used (6 log cfu/lens) and increasing initial bacterial concentration did not increase adhesion. P. aeruginosa adhered in higher numbers to high Dk compared to low Dk lenses (2 logs increase) whereas S. maltophilia adhered in higher numbers to low Dk lenses (1 log increase). Lens wear did not significantly affect the adhesion. Conclusions: S. maltophilia, commonly found in contact lens cases of Polyquaternium/Aldox care systems, can adhere at least as
improved formulations for eradicating biofilms from contact lens cases. http://dx.doi.org/10.1016/j.clae.2013.08.136 74 Antimicrobial efficacy of multipurpose disinfecting solutions against clinical isolates after prolonged storage Marina Milenkovic (Bs) ∗ , Nancy Brady (Bs), Anthony Lam (Bs), James Cook (Bs) E-mail address: [email protected] (M. Milenkovic). Purpose: To compare antimicrobial efficacy of commercially available multipurpose disinfecting solutions (MPS) against Gramnegative clinical isolates following prolonged storage in lens case in the presence of a lens. Method: The multipurpose disinfecting solutions studied were - MPS-1: polyquaternium (PQ1) + alexidine dihydrochloride (ALX), MPS-2: PQ1 + polyhexamethylene biguanide (PHMB), MPS-3: PQ1 + myristamidopropyl dimethylamine (ALDOX) and MPS-4: PQ1 + ALDOX+ nonanoyl ethylenediaminetriacetic acid (EDTA). Test solutions were inoculated with Gram-negative clinical isolates in the appropriate lens case, in the presence of Acuvue2 (etafilcon A) lens. Test solution efficacy was evaluated at minimum recommended manufacturer disinfection time of6 hours and following prolonged storage. Test solutions were also inoculated with Gram-negative clinical isolates in the test tube and tested according to ISO 14729. Results: After 6 hours exposure, MPS-1 and MPS-2 showed > 3 log kill against clinical isolates in a test tube, while MPS- 3 and MPS4 failed stand-alone criteria. MPS-1 and MPS- 2 maintained efficacy in the lens case in the presence of Acuvue2 lens and achieved > 2.5 log kill. MPS-3 and MPS-4 showed < 1 log kill or organism regrowth at 6 hours exposure. Following 7 days storage in a lens case, MPS1 achieved > 3 log kill for all organisms tested. MPS-2 and MPS-3 failed to achieve 3 log kill for one organism tested. MPS-4 failed to achieve 3 log kill for two organisms tested. Following 30 days storage in a lens case, MPS-1, MPS-2 and MPS-3 achieved > 3 log kill for all organisms tested, while MPS-4 failed to achieve 3 log kill for two organisms tested. Conclusions: Gram-negative clinical isolates are resistant to MPS-3 and MPS-4. MPS-1 and MPS-2 showed ability to reduce microbial load under worst case conditions, tested in a lens case with Acuvue2 lens present http://dx.doi.org/10.1016/j.clae.2013.08.137 75 In vitro efficiency of contact lens care solutions in removing cholesterol deposits from silicone hydrogel contact lenses Lakshman Subbaraman (PhD, BSOptom, MSc, FAAO) ∗ , Hendrik Walther (MSc), Lise Kay (BSc), Lyndon Jones (PhD, FCOptom, FAAO) E-mail address: [email protected] (L. Subbaraman). Purpose: To determine the efficiency of multi- purpose solutions (MPS) and saline in removing cholesterol deposits from silicone hydrogel (SH) contact lens materials using an in vitro model. Method: Six SH lens materials: senofilcon A, comfilcon A, balafilcon A, lotrafilcon A, lotrafilcon B and lotrafilcon B toric were removed from the blister pack, incubated for 7 days at 37 ◦ C in an artificial tear solution (ATS) containing 14-C radi-
e41
olabelled cholesterol. Thereafter, lenses were cleaned with an unpreserved saline solution (Sensitive Eyes) or one of five MPS (Opti-Free® PureMoist®, renu fresh, RevitaLens, Biotrue, SoloCare Aqua), according to the manufacturer recommendations, and stored in a vial containing the MPS. Lenses were then extracted with 2:1 chloroform:methanol, radioactive counts were determined and g/lens of cholesterol was determined. Results: Balafilcon A and senofilcon A showed the highest amounts of cholesterol deposition before cleaning (0.93 ± 0.02 g/lens, 0.95 ± 0.01 g/lens respectively), while lotrafilcon A and lotrafilcon B deposited the lowest amounts (0.37 ± 0.03; 0.47 ± 0.12). OptiFree PureMoist removed more cholesterol than the other solutions for all lens materials combined (p < / = 0.009); however, the amount of cholesterol removedwassignificantforindividuallensmaterialsbalafilcon A and senofilcon A (p = 0.006 and p = 0.042). Sensitive Eyes saline and other MPS evaluated showed no significant effect on lipid removal from the lenses tested (p > 0.05). Conclusions: Lipid-removal efficacy varies depending on the combination of lens material and solution. Only one MPS showed a significant reduction in cholesterol deposition for any of the lenses tested. It will be valuable to conduct further work to determine the efficacy of MPS in removing lipid deposits on worn lenses and how these deposits may impact subjective comfort. http://dx.doi.org/10.1016/j.clae.2013.08.138 76 Formation of biofilms of Stenotrophomonas maltophilia and Pseudomonas aeruginosa on contact lenses Mark Willcox (BSc, PhD) ∗ , Ajay Vijay (BOptom, PhD) E-mail address: [email protected] (M. Willcox). Purpose: Contact lens cases can become contaminated with high levels of Gram-negatives (e.g. S. maltophilia). Amount of contamination is dependent on the type of multipurpose disinfecting solution (MPDS) that is used, (certain MPDS containing Polyquaternium/Aldox have highest contamination). High levels of Gram-negative case contamination are associated with higher levels of infiltrates during lens wear. Bacteria colonise contact lenses and are transferred into the eye. Our aim was to determine the ability of S. maltophilia and Pseudomonas aeruginosa to form biofilms on contact lenses. Method: Clinical isolates of S. maltophilia and P. aeruginosa were grown, suspended at 1.0 x105 to 1.0 x109 cfu/ml and allowed to adhere to lenses (silicone hydrogel high Dk or HEMA-based low Dk). Numbers of cells on lenses were examined by culture. Effect of wear on bacterial adhesion was assessed after 1 day lens wear. Subjects signed informed consent and the Declaration of Helsinki for use of human subjects was followed. Results: Adhesion of P. aeruginosa to low or high Dk lenses increased with increasing inoculum, reaching a maximum (6 log cfu/lens) when 1x109 cells were added to high Dk lenses. Each 10 fold increase in inoculum resulted in 10 fold increase in adhesion to lenses. For S. maltophilia, adhesion was maximal when 1x105 cells were used (6 log cfu/lens) and increasing initial bacterial concentration did not increase adhesion. P. aeruginosa adhered in higher numbers to high Dk compared to low Dk lenses (2 logs increase) whereas S. maltophilia adhered in higher numbers to low Dk lenses (1 log increase). Lens wear did not significantly affect the adhesion. Conclusions: S. maltophilia, commonly found in contact lens cases of Polyquaternium/Aldox care systems, can adhere at least as