Serratia glossinae sp. nov., isolated from the midgut of the tsetse fly Glossina palpalis gambiensis

Abstract

We report the isolation of a novel bacterium, strain C1T, from the midgut of the tsetse fly Glossina palpalis gambiensis, one of the vector insects responsible for transmission of the trypanosomes that cause sleeping sickness in sub-Saharan African countries. Strain C1T is a motile, facultatively anaerobic, rod-like bacterium (0.8–1.0 μm in diameter; 2–6 μm long) that grows as single cells or in chains. Optimum growth occurred at 25–35 °C, at pH 6.7–8.4 and in medium containing 5–20 g NaCl l−1. The bacterium hydrolysed urea and used l-lysine, l-ornithine, citrate, pyruvate, d-glucose, d-mannitol, inositol, d-sorbitol, melibiose, amygdalin, l-arabinose, arbutin, aesculin, d-fructose, d-galactose, glycerol, maltose, d-mannose, raffinose, trehalose and d-xylose; it produced acetoin, reduced nitrate to nitrite and was positive for β-galactosidase and catalase. The DNA G+C content was 53.6 mol%. It was related phylogenetically to members of the genus Serratia, family Enterobacteriaceae, the type strain of Serratia fonticola being its closest relative (99 % similarity between 16S rRNA gene sequences). However, DNA–DNA relatedness between strain C1T and S. fonticola DSM 4576T was only 37.15 %. Therefore, on the basis of morphological, nutritional, physiological and fatty acid analysis and genetic criteria, strain C1T is proposed to be assigned to a novel Serratia species, Serratia glossinae sp. nov. (type strain C1T =DSM 22080T =CCUG 57457T).