Henri Sueke1, Stephen Kaye1, Mark C Wilkinson2, Stephnie Kennedy3, Victoria Kearns3, Yalin Zheng3, Paul Roberts4, Stephen Tuft5, Timothy Neal4. 1. St. Paul's Eye Unit Royal Liverpool University Hospital, Liverpool, United Kingdom 2Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom. 2. Institute of Integrative Biology, University of Liverpool, Liverpool, United Kingdom. 3. Department of Eye and Vision Science, Institute of Ageing and Chronic Disease, University of Liverpool, Liverpool, United Kingdom. 4. Department of Medical Microbiology, Royal Liverpool University Hospital, Liverpool, United Kingdom. 5. Moorfields Eye Hospital, London, United Kingdom.
Abstract
PURPOSE: To investigate the toxicity and corneal pharmacokinetics of meropenem as a potential antimicrobial for bacterial keratitis. METHODS: Corneal epithelial cell and keratocyte toxicity was investigated using methyl thiazolyl tetrazolium (MTT) and LIVE/DEAD assays. The penetration of meropenem through the human cornea was measured using an artificial anterior chamber. In one group of corneas, the epithelial and endothelial layers were removed and in a second group these layers were left intact. We applied 50 μL (10 mg/mL) meropenem to the corneal surface and collected samples in the anterior chamber from 45 minutes up to 24 hours. Meropenem concentrations were estimated with a bioassay and HPLC. RESULTS: Meropenem had significantly higher cellular metabolic activity (MTT assay) at both 5 mg/mL and 2.5 mg/mL compared with moxifloxacin (P = 0.029 and P = 0.018, respectively), with 96% cell viability (LIVE/DEAD assay). The measured values for meropenem concentrations in corneal and aqueous samples were significantly higher using a bioassay than with HPLC (P = 0.004). For both intact and denuded corneas, the concentrations in the anterior chamber increased from 0.48 μg/mL (SD 0.89) and 0.89 μg/mL (SD 0.81) to 6.35 μg/mL (SD 0.81) and 13.48 μg/mL (SD 14.82) using HPLC, and from 0.68 μg/mL (SD 1.50) and 1.31 μg/mL (SD 1.55) to 47.03 μg/mL (SD 5.51) and 43.69 μg/mL (SD 27.22) measured with a bioassay. CONCLUSIONS: Meropenem has very low toxicity in vitro. It has good corneal penetration, achieving anterior chamber concentrations above MIC90 for bacteria such as Staphylococcus aureus, Pseudomonas aeruginosa, streptococci, coagulase-negative staphylococci, and the Enterobacteriaceae.
PURPOSE: To investigate the toxicity and corneal pharmacokinetics of meropenem as a potential antimicrobial for bacterial keratitis. METHODS: Corneal epithelial cell and keratocyte toxicity was investigated using methyl thiazolyl tetrazolium (MTT) and LIVE/DEAD assays. The penetration of meropenem through the human cornea was measured using an artificial anterior chamber. In one group of corneas, the epithelial and endothelial layers were removed and in a second group these layers were left intact. We applied 50 μL (10 mg/mL) meropenem to the corneal surface and collected samples in the anterior chamber from 45 minutes up to 24 hours. Meropenem concentrations were estimated with a bioassay and HPLC. RESULTS:Meropenem had significantly higher cellular metabolic activity (MTT assay) at both 5 mg/mL and 2.5 mg/mL compared with moxifloxacin (P = 0.029 and P = 0.018, respectively), with 96% cell viability (LIVE/DEAD assay). The measured values for meropenem concentrations in corneal and aqueous samples were significantly higher using a bioassay than with HPLC (P = 0.004). For both intact and denuded corneas, the concentrations in the anterior chamber increased from 0.48 μg/mL (SD 0.89) and 0.89 μg/mL (SD 0.81) to 6.35 μg/mL (SD 0.81) and 13.48 μg/mL (SD 14.82) using HPLC, and from 0.68 μg/mL (SD 1.50) and 1.31 μg/mL (SD 1.55) to 47.03 μg/mL (SD 5.51) and 43.69 μg/mL (SD 27.22) measured with a bioassay. CONCLUSIONS:Meropenem has very low toxicity in vitro. It has good corneal penetration, achieving anterior chamber concentrations above MIC90 for bacteria such as Staphylococcus aureus, Pseudomonas aeruginosa, streptococci, coagulase-negative staphylococci, and the Enterobacteriaceae.
Authors: Daniel M Foulkes; Keri McLean; Yalin Zheng; Joscelyn Sarsby; Atikah S Haneef; David G Fernig; Craig Winstanley; Neil Berry; Stephen B Kaye Journal: Biochem J Date: 2021-02-12 Impact factor: 3.857
Authors: Danielle J Ingle; Rebecca L Ambrose; Sarah L Baines; Sebastian Duchene; Anders Gonçalves da Silva; Darren Y J Lee; Miriam Jones; Mary Valcanis; George Taiaroa; Susan A Ballard; Martyn D Kirk; Benjamin P Howden; Jaclyn S Pearson; Deborah A Williamson Journal: Nat Commun Date: 2021-08-09 Impact factor: 14.919