4.2.2. Gilliamella characteristics

Smooth, white, round colonies ~2.5mm diameter that form within 2 days incubation; however, colony morphology can vary between strains (Fig. 4). Cells are Gram negative, rod-shaped, non-motile, and may form filament chains. Gilliamella is negative for catalase, nitrate reductase, and oxidase (Kwong and Moran, 2013).

The sole species described for this genus is Gilliamella apicola, a member of the family Orbaceae and class Gammaproteobacteria (Martinson et al., 2012; Kwong and Moran, 2013). In early publications (Babendreier et al., 2007; Martinson et al., 2011; Moran et al., 2012), G. apicola is referred to as the “Gamma-1” or “Gammaproteobacteria-1”.  G. apicola strains have been isolated from honey bees and bumble bees, and the type strain is G. apicola wkB1T (Kwong and Moran, 2013). The type strain can be procured from bacterial culture collections (accession BAA-2448T at ATCC, or 14804T at NCIMB). Gilliamella has been estimated to comprise 0.6-30% of bacteria in the guts of individual workers (Moran et al., 2012).