Detection of pyrogens adsorbed to intraocular lenses: Evaluation of limulus amoebocyte lysate and in vitro pyrogen tests
Received 8 October 2008; received in revised form 25 February 2009; accepted 3 March 2009.
Purpose
To determine the ability of the limulus amoebocyte lysate (LAL) assay and the in vitro pyrogen test (IPT) to detect pyrogens adsorbed to intraocular lenses (IOLs).
Setting
Berlin Eye Research Institute, Berlin, Germany.
Methods
Fifteen of each of the following IOLs were used: MicroSil MS 612 ASP, AcrySof SA60AT, Superflex, Sensar, XACT, and LS-106 IOLs. The challenge organism suspensions were 103 CFU/mL and 104 CFU/mL Escherichia coli, 103 CFU/mL and 104 CFU/mL Pseudomonas putida, and 105 CFU/mL and 106 CFU/mL Staphylococcus epidermidis. Two IOLs of each model were incubated at room temperature for at least 2 days in 0.6 mL of 1 of the suspensions. They were then gamma sterilized. The extract of 1 IOL was tested with the LAL assay; the other IOL was tested with the IPT.
Results
The LAL was negative for all incubated IOLs. The IPT was positive for all IOLs incubated in E coli and P putida suspensions, with the MicroSil MS 612 ASP, AcrySof SA60AT, XACT, and LS-106 IOLs showing a severe reaction. The Superflex and Sensar IOLs had a slight to moderate response for lower bacterial concentrations and a moderate to severe response for higher concentrations. For S epidermidis, all IOLs showed a slight IPT response except XACT IOLs, which showed a nonpyrogenic response.
Conclusions
Results indicate that the LAL test may fail to detect pyrogens adsorbed to IOLs and the IPT reliably detects pyrogens with a dose-dependent response. This has relevance in the investigation of toxic anterior segment syndrome outbreaks.
From the Berlin Eye Research Institute (Werner, Tetz), Berlin, and Qualis Laboratorium GmbH (Zwisler), Konstanz, Germany; John A. Moran Eye Center (Werner), University of Utah, Salt Lake City, Utah; and Advanced Vision Science Inc. (Mentak, Aldred), Goleta, California, USA
Corresponding author: Liliana Werner, MD, PhD, Berlin Eye Research Institute, Alt-Moabit 98/99, D-10559, Berlin, Germany.
Dr. Mentak is a consultant to and Ms. Margaret Aldred is an employee of Advanced Vision Science, Inc. Qualis Laboratorium GmbH is a service laboratory for in vitro pyrogen testing. No other author has a financial or proprietary interest in any material or method mentioned.
Presented in part as a poster at the annual meeting of the American Academy of Ophthalmology, Atlanta, Georgia, USA, November 2008.
Supported in part by a research grant from Advanced Vision Science, Inc.
ABSTRACT