Publications by authors named "Keizo Watanabe"

4 Publications

  • Page 1 of 1

Glycerol Monolaurate Inhibits Lipase Production by Clinical Ocular Isolates Without Affecting Bacterial Cell Viability.

Invest Ophthalmol Vis Sci 2016 Feb;57(2):544-50

Brien Holden Vision Institute Sydney, Australia 2School of Optometry and Vision Science, University of New South Wales, Sydney, Australia 3Vision Cooperative Research Centre, Sydney, Australia.

Purpose: We sought to determine the relative lipase production of a range of ocular bacterial isolates and to assess the efficacy of glycerol monolaurate (GML) in inhibiting this lipase production in high lipase-producing bacteria without affecting bacterial cell growth.

Methods: Staphylococcus aureus,Staphylococcus epidermidis,Propionibacterium acnes, and Corynebacterium spp. were inoculated at a density of 10(6)/mL in varying concentrations of GML up to 25 μg/mL for 24 hours at 37 °C with constant shaking. Bacterial suspensions were centrifuged, bacterial cell density was determined, and production of bacterial lipase was quantified using a commercial lipase assay kit.

Results: Staphylococcus spp. produced high levels of lipase activity compared with P. acnes and Corynebacterium spp. GML inhibited lipase production by Staphylococcal spp. in a dose-dependent manner, with S. epidermidis lipase production consistently more sensitive to GML than S. aureus. Glycerol monolaurate showed significant (P < 0.05) lipase inhibition above concentrations of 15 μg/mL in S. aureus and was not cytotoxic up to 25 μg/mL. For S. epidermidis, GML showed significant (P < 0.05) lipase inhibition above 7.5 μg/mL.

Conclusions: Lipase activity varied between species and between strains. Staphylococcal spp. produced higher lipase activity compared with P. acnes and Corynebacterium spp. Glycerol monolaurate inhibited lipase production by S. aureus and S. epidermidis at concentrations that did not adversely affect bacterial cell growth. GML can be used to inhibit ocular bacterial lipase production without proving detrimental to commensal bacteria viability.
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http://dx.doi.org/10.1167/iovs.15-17180DOI Listing
February 2016

Susceptibility of Stenotrophomonas maltophilia clinical isolates to antibiotics and contact lens multipurpose disinfecting solutions.

Invest Ophthalmol Vis Sci 2014 Dec 2;55(12):8475-9. Epub 2014 Dec 2.

School of Optometry and Vision Science, University of New South Wales, Sydney, Australia.

Purpose: To determine the susceptibility of Stenotrophomonas maltophilia to various antibiotics and contact lens multipurpose disinfecting solutions.

Methods: Forty S. maltophilia strains from contact lens cases, contact lenses, or eye swabs of contact lens wearers including 27 asymptomatic wearers and 13 keratitis patients were examined for their susceptibility to different antibiotics, using a disc diffusion assay, and to multipurpose disinfecting solutions using a broth microdilution method.

Results: Certain strains were resistant to aztreonum (15%), imipenem (93%), chroramphenicol (13%), and cefepime (8%). Two of those strains were multidrug resistant. All strains were sensitive to trimethoprim-sulfamethoxazole, tigecycline, ceftazidime, and fluoroquinolones. Overall, the minimum inhibitory concentration (MIC) for all strains was significantly higher (P < 0.05) for AQuify (50% dilution) and OPTI-FREE RepleniSH (25%) than all other multipurpose contact lens disinfecting solutions (MPDS) (3%-14%, except RepleniSH versus MeniCare Soft [14%]). AQuify, OPTI-FREE RepleniSH, and MeniCare Soft had significantly higher minimum bactericidal concentrations (undiluted MPDS) than other disinfecting solutions (P < 0.05).

Conclusions: The Australian ocular isolates of S. maltophilia remain susceptible to trimethoprim-sulfamethozole, tigecycline, and most fluoroquinolones. However, the isolates showed resistance to certain multipurpose disinfecting solutions.
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http://dx.doi.org/10.1167/iovs.14-15667DOI Listing
December 2014

Cyclooxygenase (COX)-inhibiting drug reduces HSV-1 reactivation in the mouse eye model.

Curr Eye Res 2009 Mar;34(3):171-6

Department of Ophthalmology, Kinki University School of Medicine, Osaka-Sayama, Japan.

Purpose: To examine the effects of COX inhibitors on suppressing HSV-1 reactivation in a mouse model.

Methods: BALB/c mice were latently infected with HSV-1 and treated by 0.1% bromfenac Na eye drops, 0.1% pranoprofen eye drops, 0.1 mg oral etodolac 4 times/day, and saline for 4 days. After reactivating the latent HSV-1, we swabbed the mouse ocular surface for the culture of the infectious virus and assessed the viral loads in the eyes and trigeminal ganglia (TGs) using real-time PCR to determine the treatment efficacies.

Results: With stimulated reactivation, 10 of 24 (41.7%), 5 of 10 (50.0%), 17 of 25 (68%), and 16 of 22 eyes (72.7%) showed positive swab results in the bromfenac Na, etodolac, pranoprofen, and saline groups, respectively; and a significant difference was seen only between the bromfenac Na and saline groups (p = 0.033). None of the three drug-treated groups showed any significant difference from the saline group in the viral DNA in the eyes and TGs (p > 0.05).

Conclusions: Bromfenac Na eye drops can suppress HSV-1 reactivation.
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http://dx.doi.org/10.1080/02713680802650377DOI Listing
March 2009
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