Bug of the Month: The Role of Staining in Filamentous Bacteria Identification

Based on experience, one of the most challenging aspects of identifying filamentous bacteria is utilizing Gram and Neisser staining. Many incorrect identifications over the years have likely been related to over-emphasis of staining reactions in various dichotomous keys. Many of these keys create a path to follow based on filament staining reactions, and unfortunately, this concept is more complicated than originally believed. Potential complicationsPossible complications in staining reactions are likely related to factors such as chemistry reactions in the wastewater, the techniques applied during staining and the highly broad potential genetic diversity within various filamentous bacteria morphotypes (how we name them