4.1.2. Microbe characteristics

Colonies smooth, white, round, ~1mm diameter, and form within 2 days (Fig. 4). Cells are Gram negative, rod-shaped, and non-motile. Snodgrassella can use citric acid or malic acid as the main carbon source; are positive for catalase and nitrate reductase activity, negative for oxidase . 

The sole species described for this genus is Snodgrassella alvi, a member of the family Neisseriaceae and class Betaproteobacteria (Martinson et al., 2012; Kwong and Moran, 2013). In early publications (Babendreier et al., 2007; Martinson et al., 2011; Moran et al., 2012), S. alvi is referred to as the “Beta” or “Betaproteobacteria”.  Snodgrassella alvi strains have been isolated from honey bees and bumble bees, and the type strain is S. alvi wkB2T (Kwong and Moran, 2013). The type strain can be procured from bacterial culture collections (accession BAA-2449T at the American Type Culture Collection in Manasses, VA, USA [ATTC] or 14803T at the National Collection of Industrial, Food, and Marine Bacteria in Aberdeen, UK [NCIMB]). Snodgrassella has been estimated to comprise 0.6-39% of bacteria in the guts of individual workers (Moran et al., 2012).

Fig. 4.  Examples of dominant gut microbiota isolated from Apis mellifera: A. Snodgrassella alvi wkB2T; B. Gilliamella apicola wkB7 (left) and G. apicola wkB1T (right); C. Gamma-2 strain PEB0191T, grown anaerobically; D. Bifidobacterium strain wkB3 (left) and Alpha-1 strain PEB0122 (right); E. enlargements of 1x1 cm sections for (left to right) S. alvi wkB2T, G. apicola wkB7, G. apicola wkB1T, Gamma-2 PEB0191T, and Bifidobacterium wkB3/Alpha-1 PEB0122.  Strains grown on heart infusion agar + 5% sheep blood at 37ºC and 5% CO2 for 48 h, or as indicated.  Images by W Kwong and P Engel.