Evaluation of whole cell fixation methods for the analysis of nanoscale surface features of Yersinia pestis KIM.

Manipulation of viable Yersinia pestis (etiologic agent of plague) in the laboratory usually necessitates elevated biosafety and biocontainment procedures, even with avirulent or vaccine strains. To facilitate downstream biochemical or physical analyses in a Biosafety Level 1 laboratory environment, effective inactivation without affecting its intrinsic properties is critical. Here, we report on the morphological and biochemical changes to Y. pestis surfaces following four different fixation methods that render the cells nonviable. The results, obtained at the single cell level, demonstrate that methanol inactivation is best able to preserve bacterial morphology and bioactivity, enabling subsequent analysis. This nanoscale evaluation of the effects of inactivation on cell morphology and surface bioactivity may provide a crucial preparatory approach to study virulent pathogens in the lab setting using high-resolution microscopic techniques such as atomic force microscopy. [ABSTRACT FROM AUTHOR]