Reply to: Disinfection in diagnostic electron microscopy prior to preparation?

Gelderblom, Hans R.; Bannert, Norbert; Pauli, Georg

doi:10.1016/j.jinf.2006.08.008

Cited by 2 publications

(1 citation statement)

References 6 publications

(8 reference statements)

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“…Exposure of lab personnel and the public by accidentally released viruses during handling of virus–infected biological material must be avoided by efficient and feasible safety precautions. Since most electron microscopes are operated at biosafety level two and below, proper sample inactivation is necessary to guarantee biosafety [ 11 , 12 , 13 ]. For diagnostic purposes, the inactivation procedures must not only inactivate the viruses, but simultaneously preserve their morphology.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Virus Inactivation by Formaldehyde to Enhance Biosafety of Diagnostic Electron Microscopy

Møller

Schünadel

Nitsche

et al. 2015

Viruses

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Formaldehyde (FA) fixation of infectious samples is a well-established protocol in diagnostic electron microscopy of viruses. However, published experimental data that demonstrate virus inactivation by these fixation procedures are lacking. Usually, fixation is performed immediately before the sample preparation for microscopy. The fixation procedure should transform viruses in a non–infectious but nonetheless structurally intact form in order to allow a proper diagnosis based on morphology. FA provides an essential advantage in comparison to other disinfectants, because it preserves the ultrastructure of biological material without interfering significantly with the preparation (i.e., the negative staining) and the detection of viruses. To examine the efficiency of FA inactivation, we used Vaccinia virus, Human adenovirus and Murine norovirus as models and treated them with FA under various conditions. Critical parameters for the inactivation efficiency were the temperature, the duration of the FA treatment, and the resistance of the virus in question. Our results show that FA inactivation at low temperature (4 °C) bears a high risk of incomplete inactivation. Higher temperatures (25 °C) are more efficient, although they still require rather long incubation times to fully inactivate a complex and highly robust virus like Vaccinia. A protocol, which applied 2% buffered FA for 60 min and a temperature–shift from 25 to 37 °C after 30 min was efficient for the complete inactivation of all test viruses, and therefore has the potential to improve both biosafety and speed of diagnostic electron microscopy.

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Section: Introductionmentioning

confidence: 99%